HomeMy WebLinkAboutAPA708OfFICE OF THE
FEDERlC !N:~PC:CT0R
1980 AUG 25 PM 1: 4 t
ANCHOR A~~
RECOMMENDED CARNIVORE CONTROL PROGRAM
FOR THE PROPOSED NORTHWEST ALASKAN PIPELINE PROJECT
INCLUDING A REVIEW OF HUMAN-CARNIVORE ENCOUNTER PROBLEMS
AND ANIMAL DETERRENT METHODOLOGY
Draft Final Report
Prepared for
Northwest Alaskan Pipeline Company
under
Contract No. 478085-9-K071
Prepared by
Erich H. Follmann
Robert A. Dieterich
John L. Hechtel
Institute of Arctic Biology
University of Alaska
July 1980
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LIST OF TABLES.
LIST OF FIGURES
INTRODUCTION. .
BACKGROUND
OBJECT! VES
APPROACH .
TABLE OF CONTENTS
PERTINENT GOVERNMENTAL REGULATIONS.
FEDERAL STIPULATIONS DEVELOPED FOR THE NWA PROJECT
STATE REGULATIONS ..
FEDERAL REGULATIONS.
CONCLUSIONS .....
REVIEW OF HUMAN-CARNIVORE ENCOUNTER PROBLEMS.
CARNIVORE PROBLEMS -AN OVERVIEW
Canids ... .
Bears ... .
CARNIVORE PROBLEMS ON TAPS
Regional Analysis ..
Analysis by Problem Category.
Remedial Action Taken ..
REVIEW OF ANIMAL DETERRENT METHODS.
ANIMAL DETERRENTS.
Fences.
Sound . . . .
Noxious Substances.
Microwave Irradiation
AVERSIVE CONDITIONING.
Emetics ...... .
Electroshock .... .
TRANSLOCATION AND DISPATCH
Canids.
Bears .
Summary
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RECOMMENDATIONS TO AVOID AND MINIMIZE CARMIVORE PROBLEMS.
GENERAL ANIMAL DETERRENT RECOMMENDATIONS
RECOMMENDED ANIMAL DETERRENT FENCES ..
Site Recommendations for Fences .
Recommended Fence Specifications.
Electric Fence ....
Gates . . . . . . . .
CONTROL OF PROBLEM ANIMALS
Suggested Guidelines.
RECOMMENDED ENVIRONMENTAL BRIEFING TOPICS.
RECOMMENDATIONS FOR ADDITIONAL STUDY OF ANIMAL DETERRENTS
LITERATURE CITED .................... .
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TABLE
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LIST OF TABLES
Individuals contacted for information on human-
carnivore problems and deterrent and animal control
methodology.
Numb~r of reported animal related problems (bites,
charges, feeding, damage, etc.) by region during
TAPS construction and operation. See text for
explanation.
Incidents of animal related problems during TAPS
construction and operation; Prudhoe Bay to Valdez.
See text for explanation.
Emetic (lithium chloride) application during TAPS
construction for animal control. See text for
explanation. Number in parenthesis represents
number of individuals.
Final control actions taken on animals along the
TAPS right-of-way during construction and operation.
See text for explanation.
Electrical specifications for and effectiveness of
black and grizzly bear deterr~nt fences as reported
by various sources.
Fence grade recommendations for NWA construction
camps and compressor station sites.
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FIGURE
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LIST OF FIGURES
Two types of deterrent fence found to be effective
for black bears (from Boddicker 1978). Not to scale.
Oblique view of recommended high, intermediate and
standard grade animal deterrent fences. Not to scale.
End view of recommended high, intermediate and standard
grade animal deterrent fences. Not to scale.
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INTRODUCTION
BACKGROUND
The proposed Northwest Alaskan Pipeline (NWA) project will traverse
areas inhabited by the grizzly bear (Ursus arctos), black bear (Q.
americanus), wolf (Canis lupus), coyote (f. latrans), red fox (V~lpes
vulpes) and arctic fox (Alopex lagopus). To a greater or lesser degree,
each of these species can rapidly habituate to artificial food sources,
such as dumps, and to accepting hand-outs from people. The extent of
this habituation and the problems it can cause for both the animals and
people became evident during construction of the trans-Alaska pipeline
system (TAPS).
Constructing a large project through expanses of relatively undis-
turbed areas requires a great deal of manpower and logistical support.
This entails import of large quantities of food and generation of large
quantities of garbage and other refuse, items which can attract carnivores
to work sites and facilities. Proper handling, storage and disposal of
food and garbage can do much to reduce the attractiveness of a project
to carnivores but even the best maintained facility will attract animals
because of odors produced. Therefore, NWA should develop and enforce a
philosophy and program to not only conduct a "clean" operation but to
implement animal deterrent methods that will reduce contact between
carnivores and pipeline workers. This program will minimize disturbances
to animals, will minimize health and safety hazards to pipeline workers,
will minimize project delays and thus ultimately contribute to a well-
managed and cost-effective construction project.
The first phase in the development of this program is manifested in
this report which reviews the state-of-the-art of approaches to animal
deterrence and methods of dealing with problem animals. The recommen-
dations that evolve from this review should form the basis of the NWA
program to avoid and minimize encounters between carnivores and pipeline
workers.
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OBJECTIVES
This project had the following objectives:
1. to review human-carnivore encounter problems on a broad scale
and as they occurred on the TAPS project,
2. to review existing and proposed laws and regulations regarding
those problems,
3. to review methods to avoid and minimize human-carnivore
encounter problems on the NWA project,
4. to recommend methods and approaches to avoid and minimize
adverse encounters between workers and carnivores along the
pipeline corridor.
APPROACH
Information for this report was obtained from published literature
and from interviews of people experienced with animal problems and
deterrent methods. Computer searches utilizing Biological Abstracts,
Index Veterinarius, Predator Data Base, Bibliography of Agriculture, and
Fish and Wildlife Reference Service were conducted. In addition, the
Bear Bibliography (Tracy et al. 1979) and the Bibliography on the
Control and Management of the Coyote and_Related Canids with Selected
References on Animal Physiology, Behavior, and Control Methods and
Reproduction (Dolnick et al. 1976) were reviewed. Of the 18,500 titles
reviewed several hundred were considered potentially relevant. Individuals
contacted for information are identified in Table 1.
Two fenced areas were visited to observe the design and construc-
tion aspects of the fences. The fence around Alyeska Pipeline Service
Company 1 S Pump Station 8 south of Fairbanks was designed and constructed
principally for human deterrence. The fence around the dump at Banff
National Park (Canada) was designed for animal deterrence, specifically
bears.
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Table l. Individuals contacted for information on human-carnivore
problems and deterrent and animal control methodology.
Name
George Selby
Gary f·1i l ke
Al Ott
Sam Aikens
Gary Brovm
Dick Shideler
Ole Hermanrude
Tom Buhite
Stephen Herrero
Ken I~ hi trnan
Bruce Paige
Perry Jacobsen
Jim Baker
Jim Gl aspe ll
Ben Hilliker
Hal Hume
Al~vind Phukan
Max vJi nkl er
John vJoods
John Gunson
Dwayne t··1a rt in
Lew Pamplin
Cliff t~artinka
Gary Bosv·Jell
Dan Hoover
~·1ary 1'1eagher
John Dalle-t~olle
Affiliation
Naval Arctic Research Lab., AK
Alaska Dept. of Fish and Game
Alaska State Pipeline Coordinator's Office
Alyeska Pipeline Service Company
t~t. ~1cKinley National Park, AK
Alaska Dept. of Fish and Game ·
Kootenay National Park, Canada
Alyeska Pipeline Service Company
University of Calgary, Canada
West Yellowstone, MT
Glacier Bay National Park, AK
Banff National Park, Canada
Baker Engineering Enterprises Ltd., Canada
Alaska Dept. of Fish and Game
Alyeska Pipeline Service Company
Alaska Dept. of Transportation and Public
Facilities
University of Alaska
Waterton National Park, Canada
Revelstoke National Park, Canada
Alberta Recreation, Parks and Wildlife
Jasper National Park, Canada
Federal Inspector's Office
Glacier National Park, MT
Baker Engineering Enterprises, Ltd., Canada
U.S. Steel Supply, San Francisco, CA
Yellowstone National Park, WY
t·1t. ~1cKinley National Park, AK
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Name
Philip Gipson
Bob Stephenson
Bob Brovm
Joe Nava
Glen Juday
Al Tovmsend
Gary ni ll er
Lee ~·1i ll er
Terry Skjonsberg
Ken Greer
Jerry Phillips
Bob Larsen
f'le l Buchholtz
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Affiliation
Alaska Cooperative Wildlife Research Unit
Alaska Dept. of Fish and Game
Alaska Dept. of Fish and Game
University of Alaska
u. s. Forest Service
Alaska Dept. of Fish and Game
University of Montana
Alaska Dept. of Fish and Game
Banff National Park
Montana Dept. of Fish and Game
Yellowstone National Park
Alaska Dept. of Fish and Game
Alaska Dept. of Fish and Game
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PERTINENr GOVERNMENTAL REGULATIONS
FEDERAL STIPULATIONS DEVELOPED FOR THE NWA PROJECT
The stipulations reviewed below represent those submitted by the
United States government for use on the NWA project. The State of
Alaska will have a set of stipulations that apply to state lands tra-
versed by the pipeline project. The content of the state stipulations
is not expected to be substantially different from the federal stipula-
tions (A. Ott, personal communication).
The seven stipulations identified relate specifically to problems
associated with encounters between people and carnivores. The NWA
project is required to comply with these stipulations during the design,
construction, operation, maintenance and termination of the pipeline
system.
Stipulation 1.6 -DESIGN CRITERIA, PLANS AND PROGRM~S. "The
COMPANY shall submit DESIGN CRITERIA to the FEDERAL INSPECTOR. It
shall also submit comprehensive plans and/or programs (including
schedules where appropriate) which ·shall include but not be limited
to the following: ... (3) camps, ... (7) environmental briefings,
... (10') liquid waste management, ... (16) quality assurance/quality
control, ... (19) solid waste management, ... (21) surveillance and
rna i ntenance ... 11
The plans and programs submitted by NvJA to comply with this sti pula-
tion should include the designs, procedures and surveillance schemes
intended to avoid, minimize and control encounters with bears and
canids along the pipeline corridor. Those of particular concern are
fence designs, solid waste management procedures, incinerator specifi-
cations and procedures, and environmental briefing contents.
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Stipulation 1.8-QUALITY ASSURANCE AND CONTROL. 11 The COMPANY
shall provide for continuous inspection of pipeline construction to
ensure compliance with the approved design specifications and these
Stipulations ... ~~ 1.8.2-11 At a minimum, the following shall be
included in the quality assurance program: (1) Procedures for the
detection and prompt abatement of any actual or potential procedure,
activity, event or condition, of a serious nature, that: ...
(c) that at any time may cause or threaten to cause: (l) a
hazard to the safety of workers or to public health or
safety ...
(8) A plan for conducting surveys and field inspections of all
facilities, processes and procedures of the COMPANY, its contrac-
tors, subcontractors, vendors and suppliers critical to the achieve-
ment of quality. 11
This stipulation requires that the NWA be able to identify and
remedy any problems regarding bears and canids that may arise, for
example, a bear mauling or exposure of a worker to a potentially rabid
animal. These procedures should be included in the quality assurance
prog~am to ensure safe working conditions and the health of workers.
Stipulation 1.10-SURVEILLANCE AND MAINTENANCE. 11 During the
construction, operation, maintenance and termination phases of the
PIPELINE SYSTEM, the COMPANY shall conduct a surveillance and
maintenance program applicable to the subarctic and arctic environ-
ment. At minimum, this program shall ... be designed to: (l)
provide for public health and safety ... 11
The surveillance program required by this stipulation should
include protection of pipeline workers from bears and canids along the
corridor. This would entail identification of problem areas or animals,
and the taking of remedial actions as appropriate.
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Stipulation 1.11-HEALTH AND SAFETY. 11 The COMPANY shall take
measures necessary to protect the health and safety of all persons
directly affected by activities performed by the COMPANY ... and
shall immediately abate any health or safety hazards. 11
This stipulation is quite similar to previously identified stipula-
tions in that it requires the NWA to protect pipeline workers from
potential hazards, including bears and canids, along the corridor. If
potential hazards with animals occur NWA should be prepared to deal with
them with appropriate control actions.
Stipulation 2.1 -ENVIRONMENTAL BRIEFINGS. 11 The C0~1PANY s ha 11
develop and provide environmental briefings for supervisory and
field personnel ... in accordance with the approved briefings plan
required by Stipulation 1.6.1.11
This stipulation requires the NWA to d~velop a program to brief
pipeline workers on environmental conditions along the pipeline cor-
ridor. This program should include warnings regarding the potential
dangers from bears and canids and the need to avoid feeding animals and
attracting them to work areas and camps. A list of suggested topics
relevant to carnivores is included in a subsequent section of this
report.
Stipulation 2.2.4 -SANITATION AND 1-JASTE DISPOSAL. 11 All HAZARDOUS
SUBSTANCES and WASTE generated in construction, operation, mainten-
ance and termination of the PIPELINE SYSTEM shall be removed or
otherwise disposed of in a manner acceptable to the FEDERAL INSPECTOR.~~
Any wastes generated at camps and work areas, such as kitchen
wastes and discarded sack lunches, must be disposed of in a manner to
avoid attracting carnivores and other scavengers. NWA should design
facilities and develop procedures to avoid or greatly minimize this
potentially serious problem. A quality control surveillance program
should include this aspect.
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Stipulation 2.16-HUNTING, FISHING AND TRAPPING. 11 The COMPANY
shall inform its employees, agents, contractors, subcontractors and
their employees of applicable laws and regulations relating to
hunting, fishing, and trapping.11
Transfer of this information should be in the Environmental Briefing
required by Stipulation 2.1.
STATE REGULATIONS
Aliska Administrative Code 5 (5 AAC) is concerned with the protec-
tion of game in the State of Alaska. The sections of this code which
are relevant to carnivores along the pipeline corridor and must be
adhered to by the NWA, are identified below.
Central to understanding the applicability of the following sections
to the NWA project is the definition of the word TAKE. The Alaska
Department of Fish and Game (1979) defines TAKE to include any manner of
disturbing an animal. Therefore, any disturbances that are specifically
included in the following sections of 5 AAC, must be avoided by the NWA
and workers under its auspices.
5 AAC 81.090. FUR ANIMALS. 11 Fur animals may be taken while hunting,
by any methods or means except those prohibited by Sec. 120 of this
chapter and the following methods and means: ... (2) by disturbing
or destroying dens ... 11
All of the canids that occur along the pipeline corridor utilize
dens during some portion of their annual life history. The NWA project
must make efforts to avoid disturbing these dens. Bears use dens from
mid-fall to late spring but, by definition (ADF&G 1979), are not in-
cluded in this restriction. However, their dens should be protected
immediately before bears enter and while they·are inside.
5 AAC 81.120. GENERAL PROVISIONS. 11 The follm<~ing methods and means
of taking game are prohibited: ... (5) by use of an airplane ... or
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other motorized vehicle for the purpose of driving, herding, or
molesting game ... 11
This regulation prevents workers on the NWA project from harassing
carnivores with motorized vehicles and airplanes.
5 AAC 81.218. FEEDING OF GA~1E. 11 Within the State of Alaska it is
unlawful to deliberately feed ·bears, wolves, foxes or wolverine or
to deliberately leave human food or garbage in such a manner that
it attracts such animals."
The intent of this regulation is quite clear. It is essential that
the NWA brief project workers on the illegality of feeding these carnivores
directly or indirectly by intentionally leaving food and/or garbage to
attract animals. Adequate designs and procedures must be developed to
properly store food and dispose of garbage.
5 AAC 81.375. TAKING GAt·1E IN DEFENSE OF LIFE OR PROPERTY. "(a)
Nothing in this chapter prohibits a person from taking game in
defense of life or property provided that: ... (2) the necessity for
taking is not brought about by the improper disposal of garbage or
a similar attractive nuisance ... 11
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This regulation allows harassing or killing animals in defense of
life or property. However, if inadequate food storage or garbage
disposal or the feeding of animals is the cause for the action, the NWA
and its contractors and subcontractors could be held liable for harassment
or killing. Therefore, it is imperative that adequate safeguards be
developed for the NWA project so that animal attraction to construction
areas and camps is avoided or greatly minimized.
FEDERAL REGULATIONS
One federal regulation applies to the bears and canids along the
pipeline corridor and other areas affected by the N~~A project. It falls
under Title IV-Fish and Wildlife Conservation.
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16 U.S.C. 742 j-l. Airborne Hunting. "Any person who ... (2) uses
an aircraft to harass any bird, fish, or other animal; or (3)
knowingly participates in using an aircraft for any purpose referred
to in paragraph ... (2); shall be fined ... All ... aircraft ... shall
be subject to forfeiture to the United States. 11
This regulation clearly prohibits NWA project workers from harassing
any animal while working from aircraft. This regulation should be
included as a topic in the Environmental Briefing.
CONCLUSIONS
The stipulations that were developed for the NWA project and other
state and federal regulations require the NWA to avoid or minimize
contacts with carnivores along the pipeline corridor. Human-carnivore
encounters during construction of the TAPS have shown that the life and
safety of pipeline workers and the animals can be threatened in these
cases. In addition, the economic losses to a project resulting from
property damage and from delays and distraction of staff can be signifi-
cant. The NWA should develop the project design, construction planning,
and surveillance activities to meet the intent of these comprehensive
and wide-ranging stipulations and regulations. To do so early in the
planning will reduce problems during construction and operation and will
result in a more safe, efficient and cost-effective project that sub-
stantially reduces effects on bear and canid populations residing along
the pipeline corridor.
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REVIEW OF HUMAN-CARNIVORE ENCOUNTER PROBLEMS
The coexistence of man and wild animals affects both in a number of
ways. Although many are positive there are also many potentially detri-
mental aspects to coexistence. The effect of man on animals entails
loss of habitat, changes in numbers and distribution, behavioral modifica-
tions or elimination. For man the effect can be annoyance, economic
loss or injury, disease and death. The degree of effect is related to
the nature and extent of the human activity and the species of animals
in the area. Where agricultural crops are planted most of the damage
occurs from herbivores, such as deer (Odocoileus sp.), and omnivores
such as raccoons (Procyon lotor) and bears which can consume or destroy
large quantities and acreages of crops. Livestock production can suffer
when in areas inhabited by carnivores and omnivores such as bears,
coyotes and foxes. The diverse diets of these animals also facilitates
their attraction to processed human foods and garbage, attractants
common to all areas of human habitation and activity.
The impacts of man 1 S activities on carnivores is the focus of
an earlier report (Douglass et al. 1980). The pr6blems encountered
between carnivores and man, emphasizing the effects on man, are reviewed
in this section. First, problems are di~cussed in a broad spectrum
reviewing North American experiences. This review is somewhat brief
since most of the information does not deal with species or problems of
specific interest or with application to Alaska. However, it does
attempt to provide an overview of the significance of the problems. The
second section deals specifically with carnivore problems that occurred
during the construction of the TAPS. The problems are quantified by
location and category. This section is the more significant and relevant
because it reflects the types and degree of animal problems that may be
experienced during construction of the proposed NWA gas pipeline project.
CARNIVORE PROBLEMS -AN OVERVIEW
The carnivores of concern in this section are the canids (wolf,
coyote, red fox and arctic fox), and the ursids (grizzly and black
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bear). These groups are treated separately because the types of prob-
lems encountered can be somewhat different.
Can ids
The greatest impact from canids in general is predation on live-
stock. Foxes prey on smaller livestock such as chickens and rabbits
especially in areas where protection for domestic animals is lacking or
inadequate. In the west, red foxes kill lambs in unprotected pastures
(Henne 1975; Munoz 1977), although the red fox is usually not considered
a major problem in sheep country.
The larger coyote is a significant predator on sheep in the western
states. Numerous articles have been written on the problem over a
period of many years. Other livestock that are preyed upon by coyotes
include goats, pigs, calves, house cats, turkeys and other poultry
(Gipson 1978). Major efforts have been made to eliminate coyotes over
wide areas using poison, traps, snares, and a variety of hunting tech-
niques (Beasom 1974; Brawley 1977; Henderson 1930; Henne 1975; Leopold
1971; Munoz 1977; Robinson 1962; Rush 1939; Stenner and Shumake 1978;
Wade 1976, 1978), however, these efforts have proved somewhat fruitless
over the long term (Bekoff 1979). Predator control has been reduced in
recent years and Terrill (1975) reports that since 1960 sheep losses to
coyotes have increased, in fact, 63 percent from 1971 to 1973 in 22
western states. Much emphasis is currently being placed on deterrents
to coyote predation and protection for livestock. These include fences,
sound, aversive agents and odor repellents (Cringan 1972; McColloch
1972; Sander 1972; Shelton 1972). These deterrents are reviewed in
subsequent sections of this report.
The vJolf in North America is no longer considered a significant
predator of livestock principally because it has been eliminated in most
areas of livestock production. However, in the past when it was more
widely distributed, it preyed on domestic livestock and was controlled
for it.
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Non-livestock related economic losses from canids have not been
well documented. Brooks et al. (1971), Urquhart (1973) and Weeden and
Klein (1971) identify some problems with arctic foxes in northern areas,
including damage to wires and cables. Probably other canids can cause
similar problems.
In most areas wild canids are not particularly feared as direct
threats to man. However, some of the canids are particularly susceptible
to diseases which are transmissable to man, primarily rabies (Chapman
1978; Kaplan 1977; Rausch 1972; Speller 1972; West 1973). Transmission
of these diseases to man is usually through unprotected family pets and
rarely from domestic livestock that come in contact with infected animals.
Sometimes canids are attracted to artificial food sources such as dumps,
or campgrounds where they are fed (Chapman 1977; Cornell and Cornely
1979; Grace 1976; Murie 1940, 1944; Ozoga 1963; VanBallenberghe et al.
1975). These situations increase the probability of direct transmission
of zoonotic diseases to man. For the most part, however, wild canids if
not habituated to artificial foods are shy and avoid direct contact with
man, thus greatly reducing the possibility of direct attacks on man.
Bears
A significant literature has been written on bear problems through-
out North America. To facilitate review black and grizzly bears are
discussed separately in this section.
Black Bear. Predation by black bears on crops and livestock is not
widespread but can be significant in localized areas. They are particu-
larly fond of honey and cause extensive damage to apiaries (Ernst 1974;
Gunson 1977; Harlow 1961; McDaniel 1974). Many attempts have been made
to deter black bears from apiaries using fences and aversive agents,
aspects that are reviewed in subsequent sections of this report. Other
agricultural impacts by black bears include feeding on crops such as
corn (Landers et al. 1979), destruction of trees by stripping bark
(Poelker and Hartwell 1973) and livestock predation (Bailey 1953;
Bersing 1956; Cahalane 1948), particularly when natural foods are in low
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abundance (Cahalane 1948). These problems are usually less severe and
more localized than damage done to apiaries.
Property damage from black bears usually results from their attempts
to get at human food, garbage or other food (Barnes and Bray 1967;
Erickson l965a; Singer and Bratton no date). In addition, Barnes and
Bray (1966) report the use of road culverts and Rowan (1945) the under-
sides of buildings as winter dens. These activities can cause indirect
damage by blocking drainage and by affecting utility systems.
Black bears because of their size and strength pose hazards to man.
They have been reported to attack man without being provoked (Norris-
Elye 1951; Townsend 1976; Whitlock 1950) but these instances are rare.
Black bears become dangerous when they are surprised, are guarding a
food cache or when a sow is protecting young. But most instances of
attack involve bears that are being fed or are using a dump as a food
source. Numerous instances of bears being fed or using dumps are re-
ported (Barnes and Bray 1967; Bersing 1956; Bray et al. no date; Chase
1971; Eager and Pelton 1980; Erickson l965a; Ernst 1974; Hatler 1967;
Herrero 1976; Meagher and Phillips 1980; Merrill 1978; Mundy and Flook
1973; Rogers et a l. 1976; Rowan 1945). Bears can become rapidly habit-
uated to these feeding conditions and lose their fear of man. When this
occurs animals can become quite bold in their approach and sometimes
attack people in their efforts to obtain food. Singer and Bratton (no
date) report that 107 injuries from black bears between 1964 and 1976
occurred in Great Smoky ~1ountain National Park. t,lany of these instances
occurred as a result of bears being attracted by handouts and garbage.
Burghardt et al. (1972) report that most bear injury reports in Great
Smoky Mountain National Park result from people feeding bears. Buskirk
(1976) reports on three black bears that caused problems at Mt. McKinley
National Park, all undoubtedly related to food. Black bears were a
significant problem at Yosemite National Park, more so than at any other
U.S. national park (Riegelhuth 1980 pers. comm.).
Grizzly Bear. Little information is available on the impact of
{ grizzly bears on livestock. The limited distribution of grizzlies
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undoubtedly accounts for this. The grizzly bear is more of a wilderness
dweller but where grazing allotments occur in grizzly habitat a conflict
exists. Undoubtedly, grizzlies occasionally prey upon cattle or sheep
in western states. Erickson (1965b) reports that brown bears on Kodiak
Island sometimes take cattle.
Property damage from grizzly bears also occurs to homesteads, field
camps and other wilderness facilities. Bee and Hall (1956), Buskirk
(1976) and Macpherson (1965) report on damage that has been caused by
grizzlies. They are generally considered to be more aggressive than
black bears and thus more dangerous.
As with black bears, grizzlies that become habituated to handouts
and garbage are prone to lose their fear of man and become more dangerous.
Feeding of grizzlies on artificial food sources is widely reported
(Buskirk 1976; Cole 1971, 1974; Craighead and Craighead 1971; Dean 196.8;
Greer 1974, 1976; Herrero l970a, 1976; 1·1artinka 1974; Stokes 1970).
Herrero (1976) reports that as many as 70 grizzly bears have been seen
at one time eating at one of the Yellowstone National Park dumps.
Injuries resulting from encounters near developments, from active
feeding, and as a result of provoking or startling grizzlies are re-
vievJed in several papers (Cahalane 1948; _Cole 1974; Erickson l965b;
Herrero l970a, b; Martinka 1974). Erickson (l965b) speculates that
there is less than one unprovoked attack by grizzlies in Alaska per
year. Herrero (1976) reports that injury rates are the highest in r~orth
America at Mt. l~cKinley National Park even though a garbage problem does
not exist as in most other national parks. Buskirk (1976) reports that
10 people were injured by grizzlies in ~1t. HcKinley National Park between
1949 and 1976. Two people were injured by grizzlies at this park dur·ing
early summer 1980 (Juday 1980 pers. comm.). Usually attacks occur as a
result of intentionally or unintentionally approaching bears too closely.
Bears that are wounded, defending a carcass or protecting young are more
prone to attack.
General. Remedial actions taken for problem black and grizzly
J. bears throughout North America range from doing nothing through harassment,
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translocation and killing. It is sometimes hoped that if nothing is
done the problem will disappear after the attractant is eliminated or
when the animal moves away from the problem site on its own. There have
been efforts in many areas to improve garbage disposal and storage.
Several papers suggest a reduction in bear problems when garbage is less
readily available to bears (Chase 1971; ~1errill 1978; Rogers et al.
1976; Schnoes and Starkey 1978), and this appears to be a solution in
many cases. Riegelhuth (1980 pers. comm.) indicated that black bear
damages in Yosemite National Park were reduced from about $113,000 in
1975 to $10,000 in 1979 principally through an improved garbage handling
program. This consisted of installation of adequate numbers of improved
garbage receptables coupled with regular collection and haulage out of
the park. Although expensive the reduction in bear damage and threats
to visitor safety made the program worthwhile. Schnoes and Starkey
(1978) obtained information from 22 U.S. national parks and found that
during 1977 garbage handling accounted for 4000 of the total 22,954 man
days spent on bear management activities. This represents a significant
amount of effort.
Aspects of translocation and killing problem bears are reviewed in
a subsequent section.
CARNIVORE PROBLEMS ON TAPS
The human-carnivore problems that were encountered during construc-
tion and early operation of the TAPS are reviewed in this section.
Problems occurred throughout all six construction sections of the
right-of-way, although north of the Yukon River they were most severe.
The data used for this review were obtained solely from the files of the
Joint State/Federal Fish and Wildlife Advisory Team (JFWAT). Their
function was to monitor pipeline construction to ensure compliance with
environmental stipulations and other state and federal regulations
pertaining to the protection of fish and game, and to provide recommenda-
tions and advice to the Alaska Pipeline Office (federal authority) and
the Pipeline Coordinator's Office (state authority).
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The information on carnivore problems that were encountered is
scattered throughout the JFWAT files and, for the most part, is included
in Narrative Surveillance Reports prepared by each of the monitors
folloWing a field tour. Milke (1977) summarized the general problem of
animal feeding during TAPS construction but did not provide quantitative
information on the problem. The information on animal problems in the
Narrative Surveillance Reports shows the scope of the problem but does
not convey its magnitude. The reason for this is that active animal
feeding and utilization of garbage by bears and canids was commonplace
in certain areas. Unless an observer related feeding incidents to a
monitor it was not reported. Additionally, after enforcement of animal
feeding violations began, many of these activities only took place when
monitors were not present. Thus, the numbers of incidents reported
here, although large, are conservative.
Regional Analysis
Carnivore related problems were encountered throughout the TAPS
right-of-way during construction. The problems were more severe in some
regions than others. The area north of the Yukon River, particularly
south of Atigun Pass, had the most consistent and significant problems.
The terminal site at Valdez also experienced a large number of problems
with black bears.
The carnivore problems encountered were tabulated by right-of-way
segments to illustrate regional differences (Table 2). This tabulation
was developed only for the area between Prudhoe Bay and Delta Junction.
The area south of Delta Junction is not traversed ~the proposed NWA
gas pipeline and, therefore, the data would not be useful to NWA for
predicting anticipated problems. In general, the problems were not as
significant south of Delta Junction, except at the Valdez terminal site.
It is obvious from Table 2 that the most significant problems
occurred between the Yukon River and Atigun Pass. Bears accounted for
122 of the reported incidents. The majority of black bear problems
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Table 2. Number of reported animal related problems (bites, charges,
feeding, damage, etc.) by region during TAPS construction and
. 1 s 1 . operat1on. ee text for exp anat1on.
Species
Grizzly Bear
Black Bear
Wolf
Red Fox
Al~ctic Fox
Total
De 1 ta Jet. to
Fairbanks
0
3
2
0
5
2
Region
Fairbanks
to Yukon R.
17
0
1
1 9
2
1source of information was JFWAT files
2Not applicable
Yukon R. to North
Atigun Pass Slope
53 15
69 2
31 32
6 4
2 11
159 62
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occurred at Five-Mile Camp and grizzly bear problems at Chandalar Camp.
The wolf problem was also significant throughout this area but the
Middle Fork Koyukuk and Dietrich River valleys experienced more problems.
The North Slope had fewer carnivore problems than the area south of
Atigun Pass (Table 2). The wolf problem was about the same and most of
these incidents extended north to the area of Happy Valley Camp. Arctic
fox problems occurred principally north of Happy Valley Camp, and red
foxes to the south. Significantly fewer bear problems were encountered
in this region and the majority of these were south of Happy Valley Camp
in the Brooks Range.
Between Fairbanks and the Yukon River only a total of 19 carnivore
problems were documented of which 17 entailed black bears (Table 2).
The area between Fairbanks and Delta Junction had the least number of
reported problems, totalling 5. These involved black bears and wolves.
Red fox problems occurred throughout the TAPS right-of-way but the
number of incidents reported (Table 2) does not reflect the actual
significance of the problem. The probable reason for this is that bear
prOblems overshadowed fox problems and attracted much more attention
because of the greater potential threat to human safety. In addition,
red foxes are more secretive in their ha~its and are considerably more
difficult tq observe than wolves and bears. Red foxes can be encountered
regularly throughout th~ region between Delta Junction and Franklin
Bluffs Camp and are attracted by artificial food sources and feeding.
The generalization on the TAPS red fox problem underestimation also
applies to the arctic fox. However, because this fox is usually found
only on the North Slope, principally north of Happy Valley Camp, prob-
lems are more localized.
There are two factors which must be acknowledged when comparing
carnivore problems regionally along the pipeline corridor. These are
the presence of camp perimeter fences and hunting. When TAPS construc-
tion camps were built, all camps south of the Yukon River were fenced
whereas those north were not. The fences were installed to prevent
human trespass and for security against theft. This was not a problem
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north of the Yukon River because of limited human habitation and restricted
access to the Haul Road.
The fences constructed at TAPS camps consisted of chainlink mesh
installed on grade to a height of 7 ft. Three strands of barbed wire
were angled outward at the top, adding about one additional foot to the
total fence height. Even though these fences were not built specific-
ally to deter animals, they undoubtedly added significantly to minimiza-
tion of animal problems at camps. A fence of this design could be
easily penetrated by a determined bear by either going over, through or
under the fence. Similarly a determined canid could rapidly dig under
these fences. No such incidents were repor.ted during TAPS construction.
A fence of this type has its greatest effect by preventing the casual
wandering animal from entering camps. The first experiences of bears
and canids north of the Yukon River probably entailed wandering into
camps out of curiosity. Once they found food there or were actively fed
they became habituated to the camps. The animals were not provided this
opportunity south of the Yukon River and thus habituation to camps was
avoided or greatly minimized. The TAPS experience with regard to fences
in part illustrates the importance of preventing animals from becoming
habituated to artificial food sources.
The factor of hunting must be considered in the evaluation of
animal problems north and south of the Yukon River. North of the Yukon
River hunting was not permitted within 5 miles either side of the
pipeline corridor. Lack of hunting pressure eliminated animal mortality
other than from natural causes, road and control kills and some trapping.
Thus some of the problems which occurred involved some of the same
animals year after year. Since animals were unmarked the incidents
reported in Table 2 could not be refined to illustrate the actual
numbers of individual animals that caused problems.
Hunting and more extensive trapping occurred south of the Yukon
River and man'y of the problem animals probably were taken during the
harvest seasons along with non-problem animals. This fact would signif-
icantly reduce the number of recurrent problems with habituated animals.
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In fact, habituated animals probably are more vulnerable to hunting and
trapping because, for the most part, they have lost much of their fear
of people. An additional consideration is that animals killed during
the season would not be available during subsequent periods to introduce
their offspring to artificial food sources and to people. The net
result of these factors is that in the area south of the Yukon River
many of the problem animals would have to become acquainted with and
habituate to artificial foods each year whereas north of the Yukon River
the animals• habituation would carry over from year to year especially
when reinforced by inadequate garbage disposal and active feeding by
pipeline workers.
It is apparent from this evaluation that the presence of perimeter
fences around camps and the occurrence of hunting s6uth of the Yukon
River contributed to the lower incidents of problems when compared to
the area north of the Yukon River. These same factors would apply
during construction of the proposed NWA pipeline.
The attitude of individuals in understanding and minimizing carni-
vore problems must also be considered. Some camp and section managers
were quite sincere in their efforts to minimize animal attractants in
their areas whereas others were negligent, especially early in the
construction phase. Thus, some areas probably experienced fewer prob-
lems because.fewer attractants were present to lure animals. Camp
fences and the occurrence of hunting must be considered in this analysis
because they would tend to reduce the problems at any one location. For
example, it would be unfair to compare the effectiveness of a manager
making a concerted effort at a camp north of the Yukon River with one
equally concerned at a camp to the south.
Analysis-by Problem Category
The following review presents the various carnivore related prob-
lems by category. The six categories are not all mutually exclusive
because some of them are related. For example, an animal reported as
being in a camp might have been eating garbage. Therefore, that incident
would be recorded in two categories.
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The six problem categories and numbers of incidents by species are
included in Table 3. The numbers represent the total occurrences that
took place throughout the TAPS right-of-way between Prudhoe Bay and
Valdez. Again, because these data were obtained from JFWAT files and,
therefore, include only instances observed by or brought to the atten-
tion of the monitors, the data represent the minimum number of occur-
rences. The total number of incidents is large but many more undoubt-
edly were unreported. This probably would not apply to animal bites
because they would require medical attention and, therefore, be reported.
Bites and Charges. A total of 21 instances of animal bites and
charges were reported (Table 3). The bites were from wolves and foxes
and usually were associated with animal feeding. Cases were reported
where foxes were enticed to jump up for food held in the hand (Milke
1977). Bites are not always serious as witnessed in one occasion when a
worker 1 S forearm was grabbed by a wolf but the skin was not broken. The
wolf could easily have broken the bones of the forearm in this situation.
Animal bites such as this can occur even when animals are not being
fed by the victim. vJhen canids and bears become accustomed to receiving
handouts from people they can become beggers and will often approach
people. In these cases, a person may be·grabbed or bitten by the animal
seeking food or when the animal responds to a kick or other behavior
intended to scare it away. Thus innocent people can be victims of
animals fed by less concerned workers.
Animals are usually destroyed if they bite people. Because foxes
and wolves can transmit rabies and other diseases to man the purpose of
destruction is to have portions of the carcass analyzed. If rabid, the
bite vi~tims must obtain a series of shots that are both uncomfortable
and will require work loss. Happy Valley Camp experienced a rabid fox
problem in spring, 1974.
Animal charges as tabulated here (Table 3) involve bears. These
can occur in a variety of situations. Where cubs are involved a female
bear is extremely dangerous and any real or imagined threat to the cubs
usually will elicit a reaction from the adult. Where habituated animals
23
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Table 3. Incidents of animal related problems during TAPS construction
and operation; Prudhoe Bay to Valdez. l See text for explana-
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ti ons.
Problem Grizzly Black Red Arctic
I Category Bear Bear ~~0 l f Fox Fox Total
Bites/Charges -4 5 10 21
( Abnormal Behavior 0 0 2 4
Under/In Buildings l 12 3 2 6 24
In Camps/Dumps 56 68 26 12 4 166
Property Damage/
Economic Loss 13 7 0 0 21
Feeding on
Garbage/Handouts ll 15 35 9 2 72
Total 85 1 07 77 25 14 308
1source of information v:a s J F\·JAT fi 1 es l ('
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are seeking a handout there approach could be interpreted as a charge in
some circumstances or, if taunted, they might charge in anger. Similarly
any attempts to scare a bear from a food source, whether garbage or
natural food, can elicit a reaction.
The nine charges reported on the TAPS project are remarkably few
when considering the numbers of animals and people involved. The low
number of charges which occurred may suggest the extent to which the
bears along the pipeline corridor had become habituated to the presence
of people and the ava i1 abi 1 i ty of garbage and handouts. This "cooperative"
association could very well reduce the need for threat behaviors by the
animals. This would probably be more a factor with black bears which
are more complacent than grizzly bears.
Abnormal Behavior. This situation entails only foxes and wolves
and consists of unusual movements or other behaviors. Only four instances
of this were reported (Table 3).
This type of behavior can reflect the health status of an animal.
Rabies, for example, is a neurological disorder which affects behavior
in its later stages. An animal that runs in circles, stumbles, attacks
inanimate objects, etc., could be suffering from rabies or another
disease. These animals must be avoided and destroyed before they cause
injury and, perhaps, transmit the disease. At least one animal collected
during the TAPS construction was rabid.
Although the cases of abnormal behavior on TAPS involved foxes and
wolves, bears are also susceptible to some of these diseases. There-
fore, they should be treated in a similar manner. Evaluations of abnor-
mal behavior should be made by a qualified individual to ensure that
animals are not unnecessarily destroyed.
Under and in Buildings. A total of 14 reports of animals in buildings
and frequenting the areas under camp facilities was reported (Table 4).
These included bears, wolves and foxes. This was a problem north of
the Yukon River particularly early in the construction phase befo1~e
buildings were skirted to prevent access to these areas.
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Both black and grizzly bears sometimes entered mess halls, kitchens
or dormitories in search of food. Sometimes doors to these facilities
were left open thus allowing easy access for animals. No reports of
foxes or wolves in buildings were found, although the various shops
around the periphery of camps could have been entered and reports not
submitted.
Animals that went beneath buildings probably were seeking shelter.
In early fall bears seek out dens in which to overwinter. Black bears
denned beneath camp buildings at Five-Mile, for example. Maintenance
workers who have to crawl beneath buildings for repairs could be endan-
gered by a bear in these close quarters.
Similarly, wolves and particularly foxes would use areas beneath
buildings for shelter. This was especially the case in winter when the
availability of these protected areas near the ever present garbage and
handouts provided an ideal situation.
Skirting of buildings prevented much of these animal entries and
alle~iated some of the problems of animals frequenting camps for purposes
other than food. Maintaining skirts in place and keeping doors closed
are the obvious solutions to keeping animals from beneath and out of
buildings.
In Camps and Dumps. The most numerous animal problem reported was
the frequenting of camps and dumps by animals (Table 3). The number
reported is undoubtedly less than what actually occurred because not all
incidents were reported.
The primary reason animals frequented these sites was to obtain
food. Garbage storage and disposal in camps was not always adequate.
Garbage stored in plastic bags and left in accessible areas were opened
by animals. Dumpsters used to store garbage could be entered easily by
bears. Incineration of garbage could not always keep up with the
accumulation. Also, incompletely burned garbage often attracted animals
to disposal sites.
Bears at certain camps had become accustomed to breaking into
trucks and buses in which garbage was left following work shifts. The
ALASKA RESOURCES IJ KRfoJa
11.1. DEPT. OF. INTERIOR
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active feeding of animals from vehicles compounded this problem. Food
was left out at kitchen entrances fortanimals who made regular rounds.
Also, workers would provide food for begging animals and to entice
others to come closer.
These various unauthorized activities made camps extremely attrac-
tive for bears, foxes and wolves. At several ·sites some animals including
bears were known to reside in camp which strongly suggests that they
were obtaining sufficient food from garbage and handouts to maintain
themselves without foraging on natural foods. Considering the quantity
of food required daily by a bear, the supplies of unnatural foods made
available must have been quite large, especially where several bears in
one camp were thought to rely solely on these sources.
The numbers of animals eating garbage and handouts along the
right-of-way at construction sites is unknown. This problem was signifi-
cant and perhaps as troublesome as the conditions in the camps. Numerous
reports were made of food and garbage left on the right-of-way after
meal breaks. Litter and animal feeding problems at worksites were as
serious as in camps but were not easily monitored. In camps it was
easier to report animal feeding because of the presence of monitors or
Alyeska representatives whereas at construction sites, often only the
work crews were present.
Property Damage and Economic Loss. Most of the damage caused by
animals was due to grizzly bears (Table 3) in Chandalar, Galbraith and
Coldfoot Camps. Bears can cause extensive damage searching for food in
buildings and vehicles. During summer 1975, 10 black bears living under
the buildings at Five-Mile Camp caused extensive damage to electrical
and plumbing installations. These kinds of animal problems can be
significantly reduced by maintaining skirts around all buildings and by
keeping doors closed. However, doors will not deter a determined
grizzly or black bear. Buildings at both Galbraith Lake and Chandalar
Camps were damaged by grizzlies after the camps were closed and abandoned.
No reports were submitted on damage caused by foxes or wolves
(Table 3). Arctic foxes have been reported to chew through various
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wires and cables (Urquhart 1973; Weeden and Klein 1971~ Perhaps
instances of chewing damage occurred from canids during TAPS but re-
mained unreported.
Economic loss caused by animals can occur when a carnivore, par-
ticularly a bear, enters a construction site. When these animals are
aggressive or show little hesitation about approaching people, the crew
scatters and work essentially stops until the animal is scared off or
leaves by its own accord. Similarly picture taking by workers when an
animal is near reduces work productivity. When animals have become
habituated to eating garbage and handouts these problems are recurring.
In summer 1975, grizzly bear cubs and yearlings were visiting work sites
regularly, causing work delays in an area south of Glennallen. A female
grizzly with three young caused a work stoppage at Atigun Pass during
TAPS repair work in 1979.
Feeding on Garbage and Handouts. The 72 reported sightings of
animals feeding on garbage and handouts (Table 3) does not reflect the
magnitude of the problem. The problem was constant and the habituated
animals that resided in camps or frequently visited camps, dumps and
construction sites were eating at every opportunity. Many of the 166
sightings of animals in camps and dumps (Table 3) probably involved
animals in search of food or actually eating, but those behaviors were
either not observed or reported. The problem occurred throughout the
TAPS right-of-way but, as discussed under a previous section (Regional
Analysis), there were some places that had more severe problems than
others. These were usually north of the Yukon River, although the
Valdez terminal site had significant black bear problems.
The problem of active animal feeding occurred throughout the
construction phase of the TAPS project. Although workers were advised
at environmental briefings prior to entering the field that animal
feeding was prohibited, many, or at least some, ignored the restriction.
The initial violations undoubtedly set the stage for the significant and
regular problems that occurred throughout the construction phase of TAPS
and that are still ongoing in certain areas north of the Yukon River.
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c-These animals learned early in the project that people were sources of
easily obtained food and they rapidly became habituated to this situa-
tion. Panhandling was rampant and hazardous working and living conditions
in certain areas and camps were created.
The problem of animal feeding became so serious that, in July 1976,
the Alaska Department of Fish and Game (ADF&G) issued an emergency
regulation prohibiting the active feeding of bears, wolves, foxes and
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wolverines and leaving garbage exposed within the pipeline corridor.
This was about 1-l/2 years after Haul Road construction began, and
animals were already well habituated to feeding on artificial food
sources. According to Milke (1977) passage of this regulation did not
significantly alleviate the problem during the remainder of the summer.
State of Alaska 5 AAC 81.218 was passed in early 1977 which prohibited
animal feeding statewide but it was too late to be of much use during
TAPS construction. The occurrence of panhandling bears on the Haul Road
during 1980 (Hechtel pers. comm.; Wrightsman, pers. comm.), 3 years
after TAPS construction, suggests that this behavior is still being
encouraged by truckers and others using the road.
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Remedial Actions Taken
Depending on the species and circumstances involved actions taken
by pipeline workers and ADF&G personnel ranged from ignoring problems to
hazing, translocations and shooting. The data on these various activities
is incomplete and difficult to interpret. Both Alyeska and ADF&G
personnel were involved with these activities and JFWAT monitors did not
always have access to the details of translocation or control kill
operations. Therefore, the information in surveillance reports is
sometimes incomplete or lacking. The ADF&G Fairbanks office compiled a
list of bear incidents and remedial actions taken for the area north of
the Yukon River. This information was used in conjunction with JFWAT
data to compile records of control actions taken.
During construction several hazing operations were conducted at
problem areas. Cracker shells (explosive devices fired from 12-gauge
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shotguns), M-80 fire crackers, vehicles and helicopters were used to
harass problem animals (Milke 1977). Repeated use of cracker shells and
M-80's, however, was sometimes ineffective. Kennedy (pers. comm., in
Bellringer 1974) using cracker shells was able to scare red foxes away
from a camp for up to three days but he felt that they would soon ignore
the shells.
The emetic, 1 ithium chlo1~ide, was used by JFvJAT personnel in
association \'Jith R. A. Dieterich of the University of Alaska's Institute
of Arctic Biology, but this program was sporadic and not consistently
applied. Grizzly bears, black bears, wolves and a red fox were dosed
but the results were inconclusive (Table 4) due to lack of controlled
application and inability to keep track of treated animals not otherwise
marked. Additional information on this program is included in a following
section on emetics.
Final control actions included translocation and shooting. The
numbers of these events are included in Table 5. These data should be
fairly complete because usually either agency or pipeline supervisory
personnel were involved. These numbers do not include road kills or
poached animals. The killed column includes animals that were injured
during a control action and presumably djed later. The translocation
data clearly reflect the policy of killing problem black bears and
translocating other than incorrigible grizzly bears.
One grizzly bear was trapped in the vicinity of Chandalar Camp and
translocated away from the corridor. The same bear caused problems
later at Happy Valley Camp (Reynolds 1980 pers. comm.). The bear was
again translocated to an area far to the east of the pipeline corridor
on Red Sheep Creek. From there it moved about 70 miles north where it
caused problems at a camp at Peters Lake. It was later shot at a guide's
camp after it became belligerent. This example illustrates that trans-
location may only be a temporary solution for bears which have been
shown to have quite effective homing capabilities (see the section on
Translocation in this report). It also illustrates that translocation
of bears'is not a panacea because once a bear is habituated to human
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Table 4. Emetic (lithium chloride) application during TAPS construction
for animal control.1 See text for explanation. Number in
parenthesis represents number of individuals.
Immediate Long-Term
Species Result Result
\JJo l f (4) Not Seen Again Not Seen Again
\JJo l f (2) Not Seen Again Seen 3 Mos. Later
Wolf Did Not Leave Did Not Leave
Red Fox Not Seen Again Not Seen Again
Black Bear Would Not take Bait Stayed Around
Black Bear Got Sick No Data
Grizzly Bear ( ll) No Effect Stayed Around
Gdzzly Bear Apparently Got Sick Came Back
Grizzly Bear Got Sick No Data
1source of information was JFWAT files
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Table 5. Final control actions taken on animals along the TAPS
right-of-way during construction and operation.1 See text
for explanation.
Species
Grizzly Beal~
Black Bea1~
Wolf
Fox 2
Translocated
1 2
1
0
0
1source of information was JFWAT files and ADF&G data
2species unidentified
Ki 11 ed
13
25
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presence and food it may continue to behave in this manner at its new
location and be killed. Translocation can solve the immediate problem
but the bear 1 s life is still jeoparized because its lifestyle was
negatively altered by the pipeline project.
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REVIEW OF ANIMAL DETERRENT METHODS
Conflicts between wild animals and people have probably occurred
ever since man's social structure evolved from a nomadic lifestyle to
one where aggregations of people developed fixed sites in the form of
homesteads and villages. Problems arose when wild animals were a~tracted
to these areas because of new and consistent food sources in the form of
cultivated crops and livestock that would be associated with agrarian
societies. In order to sustain our present lifestyle and economy,
further encroachment of man into previously undisturbed areas in the
search for natural resources must occur. These intrusions also can
attract animals to areas of human activity principally by import of
potential attractants in the form of foodstuffs and the resultant
garbage and trash. Avoidance of human-animal conflicts by either
minimizing the attractiveness of these essential materials or by exclu-
sion of unwanted animals is as much a necessity today as it was when
these conflicts first arose. Similarly, some of the approaches to
reduce conflicts are the same as used long ago, however, the level of
sophistication has increased for some, if not the effectiveness.
This section reviews approaches that have been used to deter
animals in a variety of situations. Although information is available
on other species, part1cularly birds, this discussion is restricted to
mammals. The limited data available on bears and canids necessitates
reference to work conducted on other mammals, but this is minimized as
much as practicable. This section is subdivided into three parts:
animal deterrents, aversive conditioning and translocation and dispatch.
MlH1AL DETERRENTS
In this discussion, deterrent includes any physical, chemical or
other device or approach whose purpose is to discourage the presence of
an animal in a specific area. For convenience of discussion, deterrents
are subdivided as follows: fences, sound (noise), noxious chemicals,
and microwaves.
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Fences
Fences have been used quite widely and for many years to control
movements of both domestic and wild animals. Fences act as physical
barriers to animal movements as do trenches and combinations of trenches
and fences (Fitzwater 1972; Brown 1968, in Fitzwater; Woodley 1965).
Each, individually or in combination, can be quite effective in control-
ling movements of animals depending on the quality of the barrier and
species of concern. Fitzwater (1972) provides a useful summary of the
use of fencing in wildlife management. Burris (1965) described the use
and effectiveness of big game fences in Alaska for control of moose
depredation. One of the most spectacular uses of animal control fences
is in Australia where thousands of miles of barrier fences have been
constructed to deter passage of the dingo, a form of feral dog (Bauer
1964; McKnight 1969). Although not completely effective, these fences
have been successfully employed to reduce the predation of dingos on
sheep.
The NWA pipeline project will face encounters with black and grizzly
bears, wolves, coyotes, red foxes, arctic foxes and dogs. The type of
barrier fence to deter these various species will differ to some degree
based principally on the physical and behavioral characteristics of
these animals. Therefore, the following discussion of barrier fences is
subdivided according to species of animals that are similar in their
ability to confront and pass a barrier fence.
Red and Arctic fox. Little published data is available on the use
of fences to control movements of foxes. However, fences have long been
used to protect poultry yards from raiding foxes. The mesh size of
these fences is an important consideration since a 6-inch mesh was found.
to be ineffective in deterring red foxes in Illinois (Follmann unpub-
lished data). A 4-inch or smaller mesh size would seem necessary to
deter any adult red or arctic fox but 4-inch might permit pups to
penetrate the barrier.
At the Naval Arctic Research Laboratory (NARL) in Barrow, Alaska,
standard 2-inch-mesh chain link fence was used to pen arctic foxes.
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This fence eliminated any possibility for fence penetration but in
itself would have been insufficient in preventing escape of foxes.
Foxes, as well as other canids, dig well and a fence built on grade will
not necessarily deter them for long. At the NARL it was necessary to
bury the bottom of the 8-ft chain link fence to deter digging. The
fence was buried 2 to 3ft vertically in the gravel pad, and chain link
mesh was laid horizontally in the pad at the same depth. Where the pen
adjoined the side of a building standard chicken wire was laid horizon-
tally in the gravel pad to a 1-ft maximum depth. This proved unsatisfac-
tory because where the edge of the mesh was exposed the foxes learned to
dig beyond it and then tunnel under the mesh. Several animals escaped
by that route.
Arctic foxes are quite capable of climbing chain link fences.
Based on experience with red foxes in enclosed cages they too could
probably climb chain link. To deter foxes from climbing over the fence
at the NARL, a 2-ft band of thin-gauge sheet metal was nailed to the
inside of the wooden fence posts above the 6-ft chain link material,
thus yielding an 8-ft fence above ground. The animals were unable to
get a purchase on this material and thus could not climb over the fence.
Once the fence was properly buried and the sheet metal in place the pen
was quite secure in preventing escapes. A new fox pen designed for the
NARL consisted of 10ft of 2-inch chain link fence with 6ft vertically
above grade and the lower 4 ft sloped horizontally to a depth of 2-3 ft
into the gravel pad. It was topped by a 2-ft band of sheet metal. It
was felt that this enclosure would have been successful in holding both
arctic and red foxes.
Limited information is available on the use of electrical fences
for the control of foxes. However, the three papers reporting on this
type of fence (Forster 1975; Patterson 1977; Sargeant et al. 1974)
suggested its usefulness in deterring wild red foxes. The fence described
by Forster (1975) consisted of three st~ands of wire at 5.9 inch inter-
vals v1ith a total height of 17.7 inches. The fence was energized by t\<10
standard fencer units (specifications not provided). Use of this fence
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resulted in a 5-fold increase in the number of pairs of nesting sandwich
terns (Sterna sandvicensis) over the previous year when the nesting
colony was not protected from red fox predation. Patterson (1977) used
a fence similar to that described above but it included an "earth \'lire"
which was laid on the surface of the ground and connected to the fence
posts. The purpose of this wire was not explained but it could have
functioned to insure a shock when a fox attempted to crawl between it
and the "hot" wire 5.9 inches above. Also, it could have deterred
digging under the fence as barbed wire has been used to deter coyotes
(Gipson 1978; Thompson 1979). The fence was energized by a Koltek Big
Tom fencer powered by 10-volt batteries. This fence was effective in
reducing fox visits to the protected area by over two~thirds.
Sargeant et al. (1974) described a fence that is supplemented with
electrical wires for use in protecting the nests of ground nesting birds
from mammalian predators. The fence consists of a 24-inch high fence of
2-inch mesh chicken wire. Two strands of electrical wire are mounted at
an outward angle above the mesh at about 3.9 and 9.8 inches. A portable
fencer is used to energize the wires. The same fence but without the
electrical wires was used in another study area. Both fences reduced
predation by mammals, including red foxe~, thus leaving unknown the
amount of added security provided by the supplementary electrifi.cation.
It is apparent from available information that fences can be
effective in deterring both red and arctic foxes. The degree of protec-
tion afforded with non-electrified fences depends greatly on measures
taken to prevent digging under and climbing over the fence. These added
features plus the need for small mesh wire increase costs accordingly.
A less costly fence can be erected if electrification is included. The
reduced cost reflects both less expensive materials and reduced labor in
erecting the fence. However, maintenance requirements of an electrical
fence are greater to ensure that wires do not short out, to eliminate
vegetation, snow, etc. from making contact with charged wires, to charge
and replace batteries for DC units, and in maintaining a taut fence.
37
Coyotes. A great deal of effort and money has been spent to
control the movements of coyotes. The vast majority of this effort was
expended in protecti.ng sheep and other livestock from coyote predation
in the western states. The problem of deterring coyotes with fences is
similar to that of controlling foxes, the chief difference being the
coyote's larger size. Their ability to dig, climb and pass through
narrow openings requires a fence design to minimize penetration by all
of these routes. Thompson (1978) described fence-crossing methods of
coyotes and categorized them into four groups: climbing over, jumping
over, passing through and passing under. It could be assumed that these
categories would describe the behavior of other canids also.
A variety of fence designs have been deployed.to deter coyotes.
Their effectiveness varied considerably, principally dependent on the
fences capacity to deter the various fence crossing mehtods used by
coyotes. Shelton (1973, in Gipson 1978) provided a general review of
coyote resistant fences. More recent literature unquestionably favors
1 the use of electrified fences for the control of coyote predation
I ( (Anonymous 1977a, l977b; Gates 1978; Linhart et al. 1979; Shelton 1977)
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based on experimental and field evaluations. Thompson (1979) conducted
an excellent experiment evaluating 34 different fence configurations
including both electrified and non-electrified fences. From the abstract
he states "Fence height and mesh size were important factors in controlling
jumping over and crawling through, respectively. Overhangs and aprons
were necessary to preclude climbing over and crawling under fences." It
is interestin~ that the electric fence configurations that he used were
ineffective in deterring coyotes under the conditions of his experiment.
However, he did not test the design that has been found effective by
other investigators (Gates 1978).
The fence specifications recommended by Thompson (1979) for coyote
control are: height of at least 66 inches, mesh size smaller than 6 x
4 inches, an overhang and an on-grade apron of at least 15-inch-width
mesh material with openings less than 6 inches, and corners protected by
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shields to minimize climbing at these locations. DeCalesta and Cropsey
(1978) tested this type of fence under field conditions using a fence
height of 71 inches, a 16-inch overhang and a 24-inch apron. This fence
effectively deterred coyotes from entering the protected pastures
whereas sheep in surrounding pastures suffered high mortality.
The electrical fence described by Gates (1978) consists of 12
strands of alternating charged (+) and ground (-) wires varying from
4-inch separation at the bottom to 6-inch at the top. The total height
is 5 ft. An additional charged trip wire is located 8 inches from the
outside of the fence and 6 inches above the ground. A high voltage
fencer is needed to ensure a good shock and to minimize the effects of
vegetation coming in contact with the charged wire, thereby reducing
voltage. This fence design overcomes the most serious shortcoming of
conventional electrical fences, that of inadequate grounding under
certain conditions. An animal in contact with a charged wire while at
the same time insula ted from a ground by dry sn0\'1 or dry soi 1, wi 11 not
be shocked. This problem was already recognized long ago by McAtee
(1939), and use of metal matting, such as chickenwire, was recommended
under these conditions to ensure grounding. Alternating charged and
ground wires is a simpler and less costly solution. The proximity of
the wires virtually eliminates the possibility of climbing over or
through the fence without touching two wires. The charged trip wire on
the outside is effective in minimizing digging under fences but under
poor ground conditions it is possible that an animal would not be
shocked when in contact with only that wire.
It is apparent from the above review that fences can be built to
deter coyotes and, presumably, other canids of similar size. The same
fences probably would be useful in the control of wolves and dogs. The
height probably would have to be increased for wolves because of their
jumping capability. Both electric ~nd non-electric fences are effective
in controlling coyotes but, as with the previous discussion on foxes,
the non-electrified fence requires more materials and manpower to con-
struct and they are more complex. Therefore, they are more costly. The
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materials for the non-electrified fence are about 50 percent higher than
for the electrified fence (DeCalesta and Cropsey 1978), but the latter
may be more costly because of long-term maintenance requirements.
Wolves. No published data was found on fences for control of
wolves, however, some zoos obviously employ fencing and other barriers
to contain captive animals. The NARL constructed a pen for wolves that
was completely effective in maintaining captive animals. The fence
consisted of standard 2-inch mesh chain link on grade to a height of 11
ft. Buried vertically beneath the fence was 2-3 ft of perforated steel
plate (Marston matting) which was also laid horizontally at this depth
out into the pen for a distance of 5 to 6ft (Selby 1980 pers. comm.).
The matting deterred any attempts to dig out of the pen. No escapes
occurred even though up to 26 different wolves were maintained in the
pen for varying lengths of time.
Although information was not found regarding the use of electric
fences for controlling wolves, it is felt that the fence described for
coyote control (Gates 1978) \!JOuld be effective for wolves. The height
would have to be increased, perhaps, to deter jumping over the fence.
The non-electric fence described as effective for coyotes by Thompson
(1979) and DeCalesta and Cropsey (1978),-perhaps, would also be effective
with height modifications. The differential cost and maintenance
factors for electric and non-electric fences would apply as previously
described.
Grizzly and Black Bear. Fences have been successfully used to
deter both grizzly and black bears in certain instances. The black bear
is probably easier to control because of its smaller size and milder
temperament although both species are more difficult to deal with than
any of the canids.
The majority of literature on the use of fences to deter black
bears is associated with prevention of bear depredation in beeyards or
apiaries (Alt 1980; Anonymous 1970; Caron 1978; Dacy 1939; Doughty 1947;
Harlow 1962; Robinson 1961, 1963; Storer et al. 1938). The range of
dates for the above references clearly indicates that the problem of
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black bear deterrence is not an easy one to solve and may require
different approaches depending on circumstances. It is interesting to
note that over this 40-year period, only electrical fences or conven-
tional fences supplemented with electrical wires were developed. Non-
electrified fences obviously would not be effective, therefore, unless a
very costly physical barrier is erected. The non-electrified fence
recommended by Thompson (1978) for deterring coyotes was not effective
in deterring a black bear at one of the study sites. The overhang
section was merely bent backward when the bear climbed over. Open-
space-concept zoos often use moats to contain black bears but the
Alaskaland Zoo in Fairbanks uses chain link fence supplemented with
electrical wires.
Probably the principal reason for the relatively large number of
reports on electrical fences, each illustrating an improvement over
earlier designs, is the increased sophistication of electrical fence
equipment and the experience gained in different parts of the country.
Only the most current fence designs and specifications are reviewed
here.
Boddicker (1978) reviews two types of fences for control of black
bears that have been found to be effective. The principal difference is
that one is totally electrical whereas the other consists of two elec-
trical v1ires supplementing a mesh wire fence (Fig. 1). These designs
are based on experiences and specifications developed elsewhere.
Totally electric fences consisting of 4 or more strands of wire have
been developed as portable exclosures for black bears (Wynnyk and Gunson
1977).
Although smooth wire is easier to handle and install than barbed
wire there is an advantage to using the latter. Because of the heavy
fur on bears it is possible for the hair to insulate the bear from the
current thereby preventing a shock. Using barbed wire the points will
penetrate farther into the hair thereby increasing the probability for a
shock (Alt 1980; Caron 1978; Doughty 1947; Harlow 1962; Robinson 1963).
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T
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Figure l. Two types of deterrent fence found to be effective for black
bears (from Boddicker 1978). Not to scale.
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An additional advantage might be the deterrent value of the points,
however, this would not deter a determined animal.
The problem of ensuring a good ground is important if an electrical
fence is to be effective. Because dry snow and soil can insulate an
animal thus preventing a shock, two approaches have been used to over-
come this problem. A wire mesh laid on the ground on the outside of the
exclosure fence that is connected to the negative terminal of the fencer
will ensure a shock when an animal is standing on it and is simultaneously
in contact with the charged fence wires. This approach is illustrated
in Boddicker's (1978) review of useful fence designs (Fig. 1). Others
have described this approach also (Anonymous 1970; Dacy 1939; Harlow
1962; Robinson 1963; Storer et al. 1938; Gunson 1980 pers. comm.). The
other approach is to alternate charged (+) and uncharged (-) wires in
the fence such that an animal attempting to climb over or through the
fence must simultan~ously touch two wires thus eliciting a shock (Robinson
1961; Gunson 1980 pers. comm.; Boswell 1980 pers. comm.; Baker 1980
pers. comm.). Both methods will increase the likelihood for a shock but
the fence using the ground mesh would be more costly and difficult to
install. In addition, it would increase the likelihood of shocking
people who approach the fence.
Electrical fences for deterring black bears require a high voltage.
Wynnyk and Gunson (1977) used about 10,000 volts; Boswell (1980 pers.
comm.) indicated that a minimum of 4000 volts is required; and Robinson
(1961) used 10,000 volts. In the latter study when a 12-volt battery
was replaced with a 6-volt battery, thus halving the line voltage to
5000, the bears crawled through the wires because the charge was in-
sufficient to deter them. The current used in combination with these
voltages is quite low, usually in the milliamp range, for safety.
However, Baker Engineering Enterprises, Ltd. (Edmonton, Alberta) makes
fencers using l amp with voltages in excess of 4000 that can safely
energize fences without causing injury due to their very short pulse
width (75 to 250 microsecond duration). Therefore, if accidental
contact is made no injury will result because the duration of the charge
(
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on the body is extremely short. According to Boswell (1980 pers. comm.)
Underwriters Laboratory indicates a maximum duration of 300 microseconds
for these charge levels, thus suggesting the safety of their equipment.
However, this combination of voltage and amperage is quite effective in
deterring bears and other animals.
Several investigators (Alt 1980; Dacy 1939; Storer et al. 1938)
recommend that the charged wires be baited after installation and the
charge is applied. The purpose is to draw the bears to the charged
wires where they will be shocked on the nose or mouth. Once this occurs
the bears vJill be conditioned to avoid areas protected by fences.
Less published information is available on the effectiveness of
fences in the control of grizzly/brown bears than for black bears.
Electric fences consisting of one and two strands of wire were shown to
reduce predation by brown bears on red salmon on Kodiak Island (Clark
1957, 1959; Gard 1971). Haga (1974) reported that effective electrical
fences have not been developed to deter the Yeso-brown bear (Ursus
arct~s yesoensis) in Japan.
Greer (1974) reported that a 10-ft chain link fence with 3ft
buried surrounded by a 3-strand electric fence was penetrated by grizzly
bears at the West Yellowstone dump in Montana. The bears were getting
access to the dump by going over the fence. The top was inadequately
reinforced so that the weight of the bears collapsed the fence inward.
During the 1973 season ll attempts to dig under the fence were made by
grizzlies but Greer (1974) does not identify whether any were success-
ful. Grizzlies entered and exited this fenced dump at least 28 times
during the 1973 summer season. During mid-summer the electric fence was
relocated and a electrified wire attached 18 inches out from the chain
link fence. This did not deter the bears either. Greer (1974) does not
provide details of the electric fence but it is presumed that a standard
livestock fencer was used.
Whitman (1980 pers. comm.) indicated that the grizzly bear problem
at the West Yellowstone dump prior to 1974 was serious. The fence now
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used is a 10-ft chain link with 4ft buried; it was first buried at 2ft
but bears dug under it. Strands of electric wire were attached to the
outside of the fence using 110 volts AC. The charge was kept on for 30
days during 1974 and has not been turned on since. They have not had
bear problems at this dump in the last 5 years.
Meagher (1980 pers. comm.) indicated that a 9-ft chain link fence
with 3 ft buried was used in conjunction with electrification (Hepburn
1974) at Yellowstone National Park, and was effective. At one place
where the electricity had been turned off grizzly bears had dug under
the fence. As a temporary measure a 6-ft width of chain link fence was
laid on the ground and weighted with logs. This proved effective in
deterring furthe~ digging. Brown (1980 pers. comm.) used this same
fence design at the landfill in Mt. McKinley National Park and they have
not had any bear problems. He felt that addition of the electric fence
to the chain link was the main factor in solving the bear problems at
YeJlm·1stone Park.
At Jasper National Park an unburied 8-ft chain link .has not been
particularly effective in deterring grizzly bears from the dump. Bears
can go through the fence and dig under during one night (Martin 1980
pers. comm.). A similar fence is used at Banff National Park and bears
dig under it and have even gone over it (Jacobsen 1980 pers. comm.).
They have not used electric fences to supplement the chain link at these
locations but they are considering it at Jasper Park. These fences have
concrete pads at the base of the chain link that are continuous between
posts but these are not deep enough to deter bears from digging.
It is apparent from this review that grizzly bears are more diffi-
cult to deter effectively than are black bears. It would appear that
the shorter height fences used for black bears even with electrification
could be penetrated by grizzlies. This would be particularly true where
the electrical specifications of the fence are below maximum levels. A
voltage of 12,000 at 0.022 amps has been used to deter grizzly bears at
Yellowstone Park (Hepburn 1974) and at Mt. McKinley Park. Although the
high voltage with 1 amp described by Bosi'lell (1980 pers. comm.) has not
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been tried on grizzlies, it should be effective because of the high
power. Also, mesh fence laid on the ground outside of the vertical
fence was effective in deterring digging by grizzly bears (Meagher 1980
pers. comm.) as it was for black bears at Glacier Bay National Park
(Paige 1980 pers. comm.) and at an apiary (Robinson 1963). In neither
case was the mesh grounded to the fencer but this added assurance would
appear to greatly enhance the deterrent quality of the fence.
An aspect of electrical fences that was stressed by virtually all
information sources was the need to adequately maintain the fence. This
is essential to maintain the high powers necessary to deter bears. It
was reported by several that even though bears usually stay away from
fences once they have been shocked, they regularly test the fences when
there is an attractant of some kind within the exclosure. If the wires
are shorted or have reduced povJer when tested by the bears, they will
penetrate the fence by either going over, through or under the fence.
In any case, it does not appear that anything less than a very secure
and costly physical barrier in itself will be able to deter a bear if an
attractant is located on the opposite side. Only electrification has
been shown effective. Electrical specifications for various fences used
to control bears are summarized in Table .6.
General. A problem common to all animal deterrent fences is
accomodating human passage through the fence without reducing the
deterrent_qualities of the fence. Most of the areas or facilities that
were protected in the studies reviewed above required only periodic and
irregular access, there was no constant traffic. In these cases, the
problem is not as difficult to solve.
For non-electric coyote deterrent fences Gates (1978) recommends a
gate of at least 5 ft height with an outwardly angled overhang; A
6-inch square concrete sill is placed the length of the gap between gate
posts. The ~ate for the mesh wire and electrical strand fence for black
bears (Boddicker 1978) uses 5 strands of barbed wire only, 3 of which
are charged. The totally electric fence continues the 4 strands of
charged wire across the gate openning (Boddicker 1978). Both designs
~ ..,.._._ .,....._.._
(~ 0
Table 6. Electrical specifications for and effectiveness of black and grizzly bear deterrent fences
as reported by various sources./-
,--,\
Source Volts Pmp s
Pulse rate
per minute Effectiveness
Black bear
Storer et al. (1938)
Dacy (1939)
Robinson ( 1961)
II
Wynnyk & Gunson (1977)
Boswell (1980 pers. comm.)
Grizzly bear
Hepburn (1974)
l 0' 000
5,000
l 0, 000
4,000
12,000
0. 015
0. 015
0. l
l.O
0.022
30-50
30-50
60
---
*These specifications are for fencers designed by Baker Engineering Enterprises Ltd., Alberta.
short pulse duration (75 to 250 microseconds) permits use of higher amperage without danger.
Yes
Yes
Yes
No
Yes
Yes*
Yes
The
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use plastic gate handles to open and close the gate. A similar procedure
is recommended for black bear control in Manitoba (Anonymous 1970).
Robinson (1961) used wood-frame swinging gates with what appears to be
electrical wires across them. The pictures are not clear and the text
does not provide gate specifications.
Most of the dumps or landfills protected by fences use single or
double swinging gates. The double gate at Glacier Bay National Park has
a concrete sill between the gate posts to deter digging under the chain
link gate (Paige 1980 pers. comm.). The addition of electrical wires
across the outside of the gate would greatly reduce efforts to go over
or through the gate.
Australia has had trouble with dingo barrier fences particularly
with the increased cross-country travel in recent years (McKnight 1969).
Swing gates have always been used but many people fail to close them
after passing. To alleviate this problem they designed 11 motor-car
passes 11 which resemble the guards used to deter ungulates. These passes
consist of metal pipes or bars laid horizontally a few inches apart and
perpendicular to
problem but they
dingos. If they
the road axis.
have been found
work for dingos
Vehicles travel over these without
to be somewhat effective in deterring
they shquld work for other canids;
It is doubtful that these guards would
be effective to control bears because of their large feet and resource-
fulness.
however, no data are available.
Sound
Considerable literature has been written on the biological effects
of sound. However, many of these involve health related studies and the
effects of man-induced noises on domestic and wild animals. Studies of
the effects of noise on wildlife became important when environmental
impact statements were required to treat this potential mode of distur-
bance. In this regard Memphis State University (1971) was contracted to
review available literature on the effects of noise on wildlife for the
U.S. Environmental Protection Agency. Subsequently, a symposium was
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held to review this subject (Fletcher and Busnel 1978). None of the
information contained in either volume pertains directly to the use of
noise/sound as a deterrent. However, many useful generalizations are
identified that have application, principally with regard to audible
sensitivities, the nature and propagation of sound waves, the biological
significance of sound and the acute and chronic effects of sound.
From the biological standpoint, several generalizations can be made
with regard to the effects of sound on animals. There are definite
species differences in the ability to hear at different frequencies
(Brown and Pye 1975; Ewer 1973; Peterson et al. 1969) although little
information is available on threshold perception levels (Harrison 1978).
This factor must be appreciated if sound is to be used as a deterrent.
Additionally, the behavior, social environment and biological
condition (for example, reproductive status) of an animal can affect
its sensitivity to sound (Busnel 1978). Animals can habituate
to sound particularly if it is constant or of regular occurrence in their
environment (Ames 1978; Busnel 1978; Campbell and Bloom 1965; Sprocket
al. 1967). Similarly, it has been noted that animals can even habituate
to sonic booms (Cottereau 1978) although when first subjected to either
actual or simulated booms, they show some response (Bell 1972;
Cottereau 1978).
The physical aspects of sound that affect its propagation and
thereby its potential effect on animals include frequency (Hz) and sound
pressure level (or acoustic level or intensity) (dB). Environmental
aspects include atmospheric conditions, terrain, ground impedance, and
the presence of foliage or other potential barriers (Harrison 1978).
All of these factors should be considered in determining the effects of
sound on animals and in determining its utility as a deterrent.
Two approaches to the use of sound as a deterrent have been utilized
and both are currently considered viable. The first utilizes a sound
that animals find discomforting or painful which causes them to leave or
avoid an area. These sounds usually are of high intensity
(above 85 dB) and are either in the ultrasonic (above 15Hz) or audible
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(below 15Hz) range (Frings 1964; Greaves and Rowe 1969; Sprocket al.
1967). The second approach for the use of sound as a deterrent is
biosonics (or biologically significant sound) (Frings 1964; Haga 1974;
Sprocket al. 1967). This entails the playback of recordings of actual
or simulated distress or alarm calls of animals .. Both approaches have
been shown to be effective for certain species and under certain condi-
tions.
The majority of work on sound as a deterrent has b~en on ridding
areas of avian pests. Both sound (noise} and biosonics have been
useful under certain conditions and for certain species (Frings 1964;
Frings and Frings 1963).
A few studies have been conducted on mammals showing that both
sound (noise) and biosonics are somewhat effective in deterring these
animals or modifying their beha0ior. Sprocket al. (1967), working with
rats and mice, reported that both ultrasonic noise and recorded rat
distress calls reduced nesting and time spent near the sound source.
They suggested that ultrasonic sounds may never be very effective as rat
and mouse deterrents because they are more directional and attenuate
more rapidly in air than lower frequency sounds and because they do not
penetrate obstacles nor reflect around corners. An important point made
was that the distress-call technique seemed to have greater promise in
controlling rats than other sound techniques. Greaves and Rowe (1969)
felt that ultrasounds could be used to expel rodents from an area and to
maintain an area free of rodents by applying ultrasonic fields across
all entry points. The latter seemed to be most feasible.
Crummett (1970, in Memphis State University 1971) reported that
rabbits and deer were repelled by an acoustic jamming signal device
produced by a noise unit called Av-alarm. Hill (1970) rid an atomic
reactor building of bats by connecting 12 high frequency (4,000 to
18,000 Hz) dog whistles to compressed oxygen cylinders and operating them
continuously for 48 hours.
Only one report (Sander 1972) describing the effects of sound as a
deterrent for coyotes was found. This report provided only an overview
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of a project that was initiating research on the effects of sound on
coyotes. The purpose was to identify sounds that annoy, distress or
deny predation information to coyotes and which then could be generated
in pastures to deter raiding coyotes. Continuous tones, random noise,
and continuous and interrupted combinations of these were to be employed.
Results of this work have not been obtained. Information on the effects
of sound as a deterrent for foxes, wolves and dogs has not been found in
the published literature. However, Kennedy (1980 pers. comm., in
Bellringer 1974) reported that shotgun cracker shells were used to chase
red foxes from Dietrich Camp during TAPS construction. The foxes stayed
away for 3 days, but Kennedy felt that they would soon ignore the
cracker shells.
A few papers are available on the effects of noise on bears. In
Florida, Whisenhunt (1957) indicated that a "set-gun" consisting of a
shotgun pointed upward was effective in deterring black bears from an
apiary. Based on further study, however, he concluded that the "set-
gun11 was effective in stopping bears from making an initial entry but
not for those who had already tasted the honey during previous raids.
An added disadvantage was that they required regular inspection and
resetting of trip wires.
A similar approach using "weed burners 11 which shoot out a flash and
make a cracking sound, has been tested on bears in Yellowstone National
Park, but no results were provided (Jonkel 1977). Scaring devices
(unidentified) using sound were ineffective for polar bears (Thalarctos
maritimus) (Jonkel 1977), and one bear was wounded by a teleshot which
is a explosive scaring device (Schweinsburg 1977). Woods (1980 pers.
comm.) reported that wardens use cracker shells to harass problem bears.
at Revelstoke National Park (Canada). Alt et al. (1977) reported that
cracker shells were ineffective in deterring a female and four yearling
black bears.
Wooldridge and Belton (1977) synthesized nine versions of sounds to
simulate the aggressive sounds of male polar bears. One or more of
these sounds produced a behavioral effect in five captive polar bears,
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18 wild polar bears, two captive brown bears and 13 wild black bears.
Four of these sounds (unidentified) produced a greater effect than the
others.
Amplified (up to 120 dB) aggressive polar bear sounds were effective
in deterring captive polar bears, except females with cubs (Jonkel ·1977;
Schweinsburg 1977). At great distances the sounds attracted bears,
presumably because of curiosity. These sounds were found to be painful
to man at 140 to 150 dB but the pain level for bears was unknown. Where
captive animals were not able to escape the sounds, it was found that
they could become habituated to it. Wooldridge (in Schweinsburg 1977)
stated that high frequency dog scaring devices were ineffective on bears
but that automobile engine noise was effective.
The bear workshop attendants (Jonkel 1977; Schweinsburg 1977)
agreed that as bear deterrents coyote getters, teleshots and hand explo-
sive devices had limited value. On the other hand, high frequency
sounds, amplified sounds, and biosonics (for example, grizzly growls and
dog barks) were considered to have potential. Biosonics would probably
have a significant effect on bears if they could be used in conjunction
with other sensory stimuli such as scent, sight or touch (Schweinsburg
1 977).
Haga (1974) studied the effects of unpleasant and bear-frightening
sounds on the Yezo-Brown bear in Japan. The five sounds used were:
barking of many dogs; pile-hammer; gun-firing; synthesized sounds, the
principal one being a jet plane; and various high frequency sounds
(2,000 to 4,000 Hz). The sounds were tested on captive bears held in
grazing fields. No significant reaction was observed from the pile-
hammer, gun-shot or synthesized jet plarte sound. The high-frequency
sounds did not always elicit an immediate reaction but bears would show
avoidance behavior over a period of time when these sounds were produced
for extended periods. They tentatively concluded that the high frequency
sounds caused psychological stress in the bears after a period of time.
The recordings of barking dogs had the greatest effect on bears. The
frightening sound approach was concluded to be an effective deterrent
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for these bears. A notable point made was that, in general, the reactions
of bears to various sounds was most striking in younger age groups and
was gradually less in increasingly older aged bears. However, all age
groups responded about equally to the sound of barking dogs. Using
their equipment under similar environmental conditions it was also
determined that the volume of the barking dog sound was less attenuated
than pure sounds. The greater distance achieved and the greater relative
effectiveness over other sounds, suggested the value of barking dog
sounds as a bear deterrent in Japan.
It is apparent from these various investigations that the use of
sound can be effective in deterring mammals. Both pure sounds or noise
and biosonics have potential depending on the species involved and the
circumstances surrounding the situation or area where deterrence is
desired.
Several generalizations can be gleaned from this information and
applied to the potential for deterring carnivores with sound. It is
important that the hearing frequencies of the mammals of concern be
known so that the use of non-biosonic sound can be synthesized in the
range of greatest effect. Peterson et al. (1969) provided information
on coyotes, red foxes, and dogs showing that the upper frequency limits
of audibility are 80kHz, 65 kHz, and 60kHz, respectively. The only
data available on bears is on the Asiatic black bear (Selenarctos
thibetanus) showing that its upper hearing limit is 80kHz (Peterson et
al. 1969). Ranges of maximum sensitivity and other data for these
species are also provided in this paper. Since the sensitivity of
hearing varies with frequency (Ewer 1973), assumptions that species have
similar hearing abilities because they use the same frequency range,
must be made with caution. For example, becuase the coyote and the
Asiatic black bear hear within the same frequency range, does not mean
that they are equally sensitive to sound. The sensitivity of each
within the frequency range may vary, and differ between the two species.
Animals have an ability to habituate to sound especially when it is
continuous. Therefore, it appears that deterrent sounds should be
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discontinuous, irregular and even include frequency variations to minimize
the potential for habituation (Frings 1964; Frings and Frings 1963; Haga
1974; Sprock et al. 1967).
Frings (1964; Frings and Frings 1963) feels that high intensity
sounds (high dB level) probably are not necessary to produce an effective
deterrent. Unless in the ultrasonic range (above 15 kHz) these levels
could be harmful to people as has been shown in several investigations
on people and other animals (Alexander 1968; Allen et al. 1948; Kryter
et a 1 . 1 966) .
Biosonics seem to have great promise as animal deterrents because
they can be effective, they do not always require high amplification,
and they are meaningful to the animal. Frings (1964) points out several
problems in their application but which can be overcome with the accumu-
lation of more information. Whether alarm or distress calls are more
effective is probably species specific or perhaps varies depending on
the circumstances. The fidelity of sound reproduction appears to be
important for some species but not for others. The timing and spacing
of sound application is important and can only be determined effectively
by being familiar with the behavior of the species of concern.
Noxious Substances
A noxious substance, as used in this report, pertains to any
chemical compound that animals find distasteful or discomforting when
inhaled or contacted and that, therefore, has potential as a deterrent.
Emetics, whose action requires ingestion, are not included in this
category but are treated in a following section. The literature on
deterrent substances for carnivores is very limited; considerably more
is written on deterring herbivores, such as deer and insects, from agri-
cultural crops. A few papers are available on the use of noxious sub-
stances to deter dogs and coyotes but nothing was found for foxes and
wolves. The information on bears consists of anecdotal discussions
at workshops.
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The interest in developing noxious chemical deterrents for coyotes
is in response to the problem of predation on sheep. Potential deterrent
substances that could be applied to sheep to prevent coyote attacks are
being evaluated. Cringan (1972) briefly reviews the nature of the
program at Colorado State University to identify substances and evaluate
their effectiveness as odor repellents for coyotes. Indications that a
substance in the skin of toads accounts for the low predation on these
animals, particularly by coyotes, has stimulated a line of research to
determine whether this substance could be applied to sheep to deter
predation (Anonymous 1973). At the University of Wyoming about 500
different chemicals have been tested on sheep and the most promising is
the synthetic compound undecovanillylamide which tastes like Tabasco
sauce (Anonymous 1977). It is a stable compound lasting up to 6 months.
After biting treated sheep coyotes were reported to back away and, if
enough contact was made, to either rub their muzzle or seek water.
Linhart et al. (1977) identify a series of potential coyote repel-
lenti that were tested by various investigators but conclude that the
reason most of the work is not published is that the results were either
inconclusive or negative. The compounds identified are: cyclohexyl-
mercaptan, n-amyl mercaptan, cinnamic aldehyde, Bitrex, capsaicin, and
mustard oil. Linhart et al. (1977) tested six different compounds that
had potential as coyote repellents. These were: denatonium benzoate
(Bitrex), N-acetyl-4-cyclohexylmethylcychohexylamine (DRC-5593), N-amyl
mercaptan, chloropicrin, benzaldehyde, and cinnamic aldehyde. Chloro-
picrin is very volatile and, therefore, may have limited application
even though it produced the greatest response in coyotes. Liquid
cinnamic aldehyde reduced prey killing the most in the experiment but
there was evidence that coyotes could habituate to its repellent effects.
Huebner and Morton (1964) evaluated the effectiveness of five
commercially available dog repellents (product names not included) in a
controlled experiment using 60 dogs. The active ingredients of these
repellents were as follows:
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Product A:
Product B:
Product C:
Product 0:
Product E:
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oil of lemongrass and synthetic oil of mustard.
(aerosol)
tobacco dust, lemongrass oil, eucalyptol, citrol,
amyl acetate, geranium oil, methyl salicylate, and
oil lavender. (dust)
allyl isothiocyanate, bone oil, imitation oil of
sassafras, and paradichlorobenzene. (aerosol)
liquid animal bone oil. (dust)
New formula (unidentified). (pellets)
The results of this study indicated that Product B was 79 percent effective,
C was 65 percent effective, and D was 42 percent effective. Products A
and E were considered comparatively ineffective. No active chemical
ingredient was common to the three effective repellents; however,
Products C and D both contained bone oil. It is possible that some of
these repellents or ingredients therein would be effective on wild
canids. However, some or all of these may already have been included in
the tests of 500 chemicals at the University of Wyoming (Anonymous
1977).
Whether natural secretions from canids could be used as deterrents
has not been studied. However, Donovan (1967) suggests that secretions
from the anal glands of dogs may serve as a deterrent to other dogs.
A workshop on man/bear conflicts was held in Canada (Jonkel 1977;
Schweinsburg 1977). It is quite apparent that little information is
available on the use and effectiveness of chemical deterrents on bears.
Formaldehyde and a mixture of mustard oil and kerosene were ineffective
in deterring bears in Banff and Jasper National Parks. However, where
formaldehyde was applied to garbage cans, some success was achieved. It
56
( v1as agreed that noxious chemicals and natural repell ants, such as
mercaptan, had merit as deterrents but more work is necessary to deter-
mine their effectiveness (Jonkel 1977) and the best ways for application
(Schweinsburg 1977). Haga (1974) reported that chemical repellents
were ineffective against the Yezo-Brown bear in Japan.
c
A variety of deterrents are marketed for personal protection
against bear and dog attacks. These contain substances such as tear
gas, cayenne pepper and eucalyptus oil as the active ingredient. Brown
(1980 pers. comm.) of the Alaska Division of Fish and Wildlife Protec-
tion is skeptical about their effectiveness principally because thorough
studies on these substances have not been conducted. Nava (1980 pers.
comm.) found that Halt (a commercial dog repellent) caused three captive
black bears to slowly back away when this substance was sprayed in their
faces. Although these various substances are packaged for personal
protection, jt is possible that if found to be effective after more
study, they could be prepared for wider application and to deter animals
from ~pecific places or areas.
The lacrimating agents such as tear gas have been studied to some
extent, principally to determine their harmfulness to people during
crowd control. There are two basic type~ used: chloroacetophenone (CN)
and o-chlorobenzylidenemalononitrile (CS) (Gaskins et al. 1972). These
substances can cause damage to the eyes, skin and respiratory tract
depending on the dose, duration of exposure and manner of application
(Andrev1s 1964; Cucinell et al. 1971; Gaskins et al. 1972; Kalman 1971;
Leopold and Lieberman 1971; Macleod 1969). Under controlled experi-
mental conditions Andrews (1964), testing several mammal species, found
no abnormalities in a gray fox (Urocyon cinereoargenteus) 24 hours after
exposure. Cucinell et al. (1971) found that CS caused heart rate
increase, rise in blood pressure, altered breathing pattern, reduced
blood oxygen level, decreased blood pH level, and increased co 2 pressure
in the blood of a dog exposed to a high dose. If the dose level used in
this experiment could be achieved under field conditions, these reac-
[ tions would suggest that use of tear gasses could injure animals or
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cause pain. In either case the animal may become enraged and either
attack or cause unintentional injury or damage during its reaction to
the substance. These could produce more problems than if the animal was
left alone.
It is obvious from the above review that certain noxious substances
show promise as deterrents for canids and bears. However, more work
will be necessary to test these and other substances before broad
application can be attempted.
Microwave Irradiation
Microwave irradiation has been used as an animal deterrent. Ark
and Parry (1940) long ago reviewed the effects of high frequency electro-
magnetic waves on various species of animals. It was determined then
that high frequency waves heated the irradiated subject. Microwave
irradiation produces both heating and chemical effects (Baker et al.
1955). The latter involves changes in cellular metabolism (Tanner et
al. 1967). Wave lengths longer than 2880A produce heating whereas
shorter wave lengths produce chemical effects (Baker et al. 1955).
Tanner et al. (1967) irradiated chickens with microwaves and
elicited behavioral responses which presumably occurred because neural
tissue was directly affected by the microwaves. In an earlier paper
Tanner (1966, in Tanner et al. 1967) elicited avoidance or escape
reaction when chickens were exposed to microwaves that produced a
thermal effect. Both studies showed that chickens, and presumably other
birds, do respond to microwaves and, therefore, this approach could be
used as a possible deterrent. This method was being studied because it
perhaps could be applied as a deterrent for birds near airport runways.
There appears to be more work on the use of microwaves for the control
of birds but this literature was not reviewed because of its question-
able application to mammals.
King et al. (1971) tested rats and found that they were sensitive to
microwave irradiation and that it could be used as a cue for impending
electroshock in behavioral experiments. Whether animals detect microwave
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irradiation by thermal or some other sensory change is not known.
Microwaves used were 2450 ± 5 MHz at doses up to 6.4 mw/g, a value well
below the safety limit of 10 mw/cm 2 observed in the United States (King
et al. 1971). It would appear that microwaves to be used as deterrents
would have to be more powerful than used in this experiment since these
levels were essentially near the threshold of sensitivity. These higher
levels could be injurious to man.
No information has been found on the use or effectiveness of micro-
wave irradiation on larger mammals, including the carnivores. Therefore,
the potential utility of this method cannot be speculated upon in this
report.
AVERSIVE CONDITIONING
Aversive conditioning involves a process of training an animal to
avoid or reject an object, food or behavior that is normally desirable.
This is acco~plished by applying an unpleasant or painful stimulus
during the undesirable activity. For example, if an animal enters an
area which it is being trained to avoid, it can be shocked so that it
associates pain with the area~ Aversive conditioning is accomplished
with negative reinforcers such as electrical shock and emetics.
Aversive conditioning involves modifying the behavior of an animal
by pairing the target undesirable behavior with a painful stimulus.
This is in contrast to noxious chemical deterrents which repel animals
by their odor or taste, or on contact with the mouth or skin. These do
not by necessity require behavioral modification. To illustrate the
difference, if a hot dog is treated with a chemical repellent a fox will
avoid it because of the repellent. On the other hand, if the hot dog is
treated with an emetic the fox will eat the hot dog and later become
sick. Subsequently, the fox will avoid hot dogs because they are
associated with sickness. Thus the fox's natural behavior to eat hot
dogs is altered.
Aversive conditioning has been used widely in behavioral experiments
under laboratory conditions. Most of this work involved rodents. The
use of aversive conditioning in larger animals has been less studied.
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Aversive conditioning is one of the techniques that has been tested
to control predation of coyotes on livestock, especially sheep. It has
also been used to aversively condition black bears from raiding apiaries
for honey. The conditioners used in these experiments were a series of
drugs called emetics which cause nausea when ingested. The following
section discusses the use and effectiveness of emetics.
Other aversive conditioning studies in the laboratory involved the
use of electrical shock as the conditioning stimulus. A brief section
follows speculating on its use for nuisance animals.
Emetics
The use of emetics (nausea produci.ng agents) as aversive condition-
ing agents has been the subject of interest to livestock owners for the
past several years. Several different research projects have provided
valuable information on the effectiveness of these agents in preventing
or controlling predation of livestock. The majority of information
gathered relates to laboratory animals and non-Alaskan wildlife in
ranching situations of the contiguous 48 United States.
Limited experimental and field data were collected in 1976 by R. A.
Dieterich and JFWAT personnel during the construction of the TAPS.
During that study, dogs and captive wolves were fed different types of
food which contained lithium chloride in free form, in capsules and in
delayed release wraps. Dogs were easily conditioned to avoid specific
types of food and this aversion lasted for several weeks. Wolves were
more selective in what they ate and appeared more willing to retest
baited food to determine if it still contained an emetic. Wolves were
fed lithium chloride in sandwiches along the oil pipeline during its
construction phase. It was a common practice for workers to throw
sandwiches to wildlife along the haul road. This led to several prob-
lems. Not only were the health and safety of the workers jeoparized but
also many carnivores were injured or killed while frequenting roadsides
in search of handouts. The continual feeding of the animals led to
their dependence on human-supplied food sources. The baiting of sandwiches
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limited testing period and lack of marked animals did not allow any
conclusions to be made.
A study by Gustavson, et al. (1976) indicated a 30 to 60 percent
reduction in sheep killed by coyotes following application of taste
aversion conditioning agents in comparison to past loss records maintained
by individual ranchers. In this study, captive coyotes were fed rabbit
flesh treated with lithium chloride and captive wolves were fed similarly
treated sheep flesh. One or two treatments inhibited predatory attack
upon the living prey, but left the appetite for alternative prey unaffected.
The success of these first studies led investigators to try several
different agents to control wildlife interactions with man, domestic
animals or man's environment (Ell inset al. 1977; Cornell and Cornely
1979; Dorrance and Gilbert 1977; Brett et al. 1976; Rusiniak et al.
1976). The more common products used as emetic aversion control agents
include lithium chloride, sodium salicylate, syrup of Ipecae, apomorphine,
peruvoside and ouabain (Harrison et al. 1972; Wittlin and Brookshire
1965; Yeary 1972). A review of numerous articles on emetics indicates
that lithium chloride shows the most promise at this time. Baseline
information is available on its use in a -number of species. Apomorphine
is another effective product but its narcotic status limits its avail-
ability and would probably curtail widespread distribution of loaded
baits in uncontrolled areas.
Several nausea-inducing chemicals have been tested in bears to
determine their potential as aversive conditioning agents. Black bear
kills in British Columbia's interior showed a significant difference in
the rate of consumption of the carcass between chemically treated and
untreated carcasses (Wooldridge 1977). Also, lithium chloride in
combination with electric fences effected a 94 percent reduction in
damage of beeyards by black bears as compared to unprotected beeyards.
The action of nausea producing drugs depends on their effect on the
emetic apparatus located in the brain (Smith et al. 1974). This apparatus
is functional at three days of age in dogs; thus most emetics are effective
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in all age groups. Emetics as aversive conditioning agents function by
having the animal which received the baited food containing an emetic,
associate the food with an unpleasant experience. Experiments with
caged dogs and wolves in Alaska indicated this aversion is relatively
long standing (several weeks) but a limitation is that it is food
specific. A wolf fed a meat sandwich baited with lithium chloride will
avoid that type of sandwich but may well eat a fish sandwich. Reinforce-
ment with another baited sandwich may be necessary at future times to
assure success. A random baiting of food sources Which draw carnivores
to pipeline construction areas may prove effective as an inexpensive and
effective control measure in areas unsuitable for fencing. It has been
shown that location is not an ecologically important cue in bait shyness
so animals baited in one area would probably avoid similar food sources
in another area (Slotnick et al. 1977).
Several problem areas have been identified which need further study
before widespread use of emetics as aversive conditioning agents can be
started. Animals can soon learn the taste of emetics and avoid only
baited foods. This has been overcome in some cas~s by the use of cap-
sules that contain the emetic until it reaches the stomach. The rate
that these capsules dissolve is critical .because if the animals vomit
immediately after ingesting the emetic the aversive conditioning will be
lessened. Dieterich and co-workers overcame some of these problems by
wrapping the capsule containing the emetic in a plastic film which
dissolved slowly after being eaten.
The primary problems in using emetics as aversive conditioning
agents evolve around the duration of aversion possible in different
species, the specificity of aversion and the changing behavioral pattern~
of the carnivores in adapting to the presence of aversive agents in
food.
Electroshock
Electroshock has been used as a conditioning agent in many behavior
[ experiments on rodents. This usually involves an electrified cage floor
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or other device to induce a shock when an animal performs an activity
that is not desired.
Collars are commercially available for dogs that are energized and
can induce a shock by remote control. These collars are used to train
dogs for hunting and for controlling other behaviors.
It is possible that nuisance animals could be controlled with this
device if it was a situation where the animal was unsuitable for trans-
location or dispatch. Use of this technique would require live capture
of the animal, fitting with the collar, and release. Any time the
animal performed an objectionable behavior it could be shocked by
remote control. If successful, the animal would be aversively con-
ditioned to the unwanted behavior. Major disadvantages of this tech-
nique are that it is relatively expensive and time-consuming. The
animal has to be captured and handled twice (to fit it with and after-
ward remove the collar) and someone has to observe the animal during
this period to administer the shocks at the appropriate times. These
would appear to seriously reduce the utility of this technique under
field conditions with wild animals.
TRANSLOCATION AND DISPATCH
Problem animals are often dealt with in manners more direct and
final than developing deterrents to elicit avoidance of areas or food
items. The previous sections reviewed various types of deterrents and
aversive conditioning, and their effectiveness. This section briefly
reviews approaches for dealing with problem or incorrigible animals.
Problem animals are ones that either have failed to be deterred by other
methods or that pose problems as first-time offenders.
Canids
Canids, because of their predatory lifestyle, have long caused
problems in areas of livestock production and where competition with man
for game animals is considered important. Most of the literature on
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control, therefore, is related to these ~roblems and not where dumps or
other artificial food sources have attracted these animals. Foxes and
coyotes usually are shot or trapped and killed where they cause problems.
Although wolves can be dealt with in similar ways, little published
information is available because the distribution of this species is
limited in areas of human habitation, and densities are low. Exceptions
are Alaska and the northern regions of Canada. Control philosophies and
methods developed for coyotes to a large degree should be applicable to
other North American canids.
Typically, troublesome canids are eliminated by either shooting or
trapping. A series of papers has been published on this subject,
mostly on coyotes (Casto and Presnall 1944; Cowan 1949; Fitzwater 1970;
Gipson 1975; Henderson 1972; Spencer 1938; Thompson 1976). Brawley
(1977) tested several control methods for coyotes that were preying on
domestic sheep. Jackson and Davies (1973) reported on live trapping of
dogs in remote situations, however, these animals were later destroyed.
Generally, foxes and coyotes in these situations are considered vermin
and efforts are not made to live trap and move them because they might
cause problems elsewhere or perhaps even return to the original problem
area. Homing behavior in North American ·canids is virtually unknown
mostly because trapped animals are usually killed. Even where animals
are live-trapped for study they are released at the point of capture.
Homing has been reported in an adult red fox which moved 35 miles in 12
days to the area of capture (Phillips and Mech 1970). Henshaw and
Stephenson (1974) reported homing in gray wolves. One wolf raised at
the NARL and translocated near Umiat 175 miles southeast of Barrow
returned and was again caged 4 months after release. Two others were
killed midi'Jay between Umiat and BarrovJ 2 months and 7 months, respectively,
after release. Both were on a degree bearing between Umiat and Barrow
suggesting that their movements were not random. Wolves in northwestern
Alaska annually move between summer grounds on the North Slope to areas
south of the Brooks Range in winter (Stephenson 1980 pers. comm.). If a
wolf from these packs was trapped and relocated in this general area it
could be assumed that it would be able to return to the capture area.
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The costs associated with a trapping and relocation program can be
high and perhaps prohibitive in most situations. Occasionally problem
animals are live-trapped and transported to zoos or nature parks in need
of representative animals. These situations are infrequent, however,
and most nuisance animals of fox and coyote size are destroyed. Where
diseases such as rabies may cause human health problems, animals are
definitely destroyed (National Academy of Sciences 1970) for analysis of
tissue.
Bears
Bears pose a different problem because of their size, their pro-
tected or big-game status and their ability to arouse public interest.
However, where these animals become a nuisance they are either destroyed
or translocated. On the TAPS proj~ct problem bears were handled in this
way. Grizzly bears were either translocated or shot and black bears
usually shot (JFWAT files).
The circumstances surrounding the animal nuisance problem often
dictate the solution~ In northern Alberta where apiaries are an impor-
tant part of the local economy black bears cause considerable problems.
From 1972 through 1978, 2,122 problem bl~ck bears were shot with the
highest annual kill of 506 occurring in 1976 (Gunson 1979). Mortalities
of this magnitude caused some public outcry, therefore, deterrents
such as fences and aversive conditioning were tested for effectiveness.
Even where deterrents are somewhat effective the usual procedure is to
destroy an incorrigible animal.
Grizzly bears can also cause damage in agricultural regions although
population densities in these areas are usually low. Where populations
are higher, such as in western Canada and Alaska, man 1 s presence is not
as significant and, therefore, problems are not common. Problem grizzly
bears that are repeat offenders or threaten human life are usually
destroyed but are sometimes translocated (Craighead and Craighead 1971).
In Yellowstone National Park 140 grizzlies were killed between 1931 and
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1970 with 22 of those killed in 1970 (Craighead and Craighead 1971).
Destruction is usually a last resort because of the low population
densities in problem areas and to avoid public outcry.
A considerable amount of literature is available on capture and
translocation of bears, particularly black bears. Most bears are live-
trapped, drugged and released at sites distant from the problem area.
Others are captured with projectile drug syringes prior to relocation.
Both black and grizzly bears have demonstrated homing behavior, a factor
that must be considered when considering the utility of relocating bears
away from the problem area.
Black Bears. Most information on homing behavior concerns black
bears. Gunson (1979) reported that 914 bears were translocated from
1972 through 1978. Of 15 bears on which data is available seven returned
to the vicinity of capture. The distance from the capture point beyond
which some bears did not return was 29 miles. One bear returned from a
distance of 53 miles. No time intervals for return were provided in
this report. In British Columbia 37 of 54 black bears were recaptured
at the origianl site (Rutherglen and Herbison 1977). Ten of these bears
returned within one month whe~eas others.occurred within one year. Over
a period of one year a female with cubs homed three times after trans-
locations of up to 59 miles. In Newfoundland three black bears were
translocated to offshore islands (Payne 1975). Within four weeks all
had returned to the capture site which required a minimum 0.6 mile swim
through salt water and a minimum overland movement of 12 miles. In the
same study a female with cubs homed 43 miles overland in 18 days.
In New York 4 of 13 black bears demonstrated homing behavior with
one male returning to the trap site a distance of 32 miles in 8 days;
another male returned 43 miles after one year (Black 1958). Twenty of
51 black bears translocated in Pennsylvania homed (Alt et al. 1977).
Releases greater than 38 miles from the capture site reduced homing in
this study. Six of these bears were radio-tagged and it is significant
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that solitary males and females, a female with cubs, and a female with
yearling~ all exhibited homing behavior. Beeman and Pelton (1976)
reported homing behavior in black bears translocated in Great Smoky
Mountains National Park. The greatest distance moved to the capture
site by a male was 38 miles and by a female 11 miles. The farther away
the release point the less likely was the chance for homing. In the
upper peninsula of Michigan, 115 black bears were translocated in a
study of homing behavior (Hargar 1970 and 1974). Twenty-seven bears
homed and 11 others moved long distances in the direction of the capture
site. The greatest distance moved was 142.5 miles. Both males and
females had similar homing ability. Rogers et al. (1976) reported that
young male black bears in the same area were less likely to home than
older males and females.
The various reports cited above in some cases contain more detailed
information on homing behavior in black bears than reported here.
Because most of the reports involved bears without radio-tags, it is
difficult to interpret what proportion of bears will usually home.
Bears that did not home perhaps died or were translocated from a dif-
ferent problem area. However, several generalizations can be made that
are supported by most of these reports. ·Both male and female bears have
homing ability including both solitary females and ones with cubs or
yearlings. Cub and yearling black bears, when translocated without an
adult female, are less likely to home than older aged bears. The
greater the distance translocated from the capture site the less likely
will homing occur, although black bears have been shown to home over
considerable distances in a relatively short time. Bears that are
translocated tend to move a great deal more than animals released in the·
vicinity of the capture site. This may be associated with search
behavior for familiar territory but could increase the probability of
homing because these search movements often are oriented in the direction
of the capture site. The additional movement in unfamiliar territory
may also increase the probability of being killed.
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Grizzly Bears. Less information is available on homing in grizzly
bears. Craighead and Craighead (1971) reported that 145 grizzlies were
translocated in Yellowstone National Park between 1959 and 1969. Sixty-
eight percent of these bears returned to the same or another campground;
the actual number returning to the capture site was not identified.
Greer (1974) reported that of 30 grizzlies translocated from the vicinity
of West Yellowstone between 1971 and 1973, four returned within the year
of capture and four during the following year. One of the males traveled
a distance of 45 miles to return to the vicinity of capture the following
year. Craighead (1976) reports that grizzlies translocated less than 48
miles can return quickly to the point of capture. Eleven translocated
grizzlies in Yellowstone National Park in 1968 and 1969 returned 32
times to the capture area. The greatest distance returned was 28 miles.
Most of these bears were adults but yearlings returned to the capture
site four times. In the Yukon Territory, Pearson (1972) reports that
one translocated female grizzly traveled 70 miles back to its home site
in three days. P~arson (in Cowan 1972) suggests that adult female
grizzlies should be translocated at least 50 miles and males at least
100 miles if the operation is to be successful.
Although less information is availa~le on grizzly bear homing than
for black bears, some generalizations can be made. Grizzlies are able
to home great distances in a short period of time. Both adult males and
females are capable of these movements, as are yearlings. Apparently,
the farther an animal is transported from its home range the less likely
it will return.
Summary
It is obvious from the above review that both canids and bears can
home after translocation. Although only minimal data are available for
canids it appears that translocation can be successful only if animals
are moved great distances from the problem area. Several authors felt
that other management techniques were needed to deal with problem bears
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mostly because of their homing ability (Craighead and Craighead 1971;
Lindzey et al. 1976). Another reason for considering alternative plans
for dealing with problem bears is the great cost and time needed for
these operations (Alt et al. 1977; Beeman and Pelton 1976; Cowan 1972;
Greer 1974) although none of these reports specifically used this reason.
It has been suggested that black bears be moved soon after entering a
potential problem area because the chance for homing is less (Beeman and
Pelton 1976). This, however, may not be supported by other workers in
different circumstances.
Destruction of problem animals is the rule for all canids and for
bears that have taken or threatened human life or are repeat offenders.
This obviously is the least costly and time consuming method but can
induce public outcry especially when dealing with animals such as
grizzly bears and even wolves. Recent treatises on predator management,
which in this context is a problem similar to that faced with animals
concentrating at artificial food sources, suggest that if control is
necessary the offending animals should be dealt with and not necessarily
all members of the species that happen to be in the area (Berr~nan 1972;
McCabe and Kozicky 1972). In addition, conditions contributing to the
problem should be reviewed prior to taking control actions and, if
control is necessary, alternatives should be evaluated (McCabe and
Kozicky 1972). Thus, animal control should not be the first subject
addressed, but should be considered only after conditions contributing
to or causing the problem are remedied, if this is possible.
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RECOMMENDATIONS TO AVOID AND MINIMIZE
CARNIVORE PROBLEMS
The NWA project will be faced with the same problems that TAPS
encountered because the proposed gas pipeline will traverse areas
inhabited by both black and grizzly bears, wolves, and red and arctic
foxes. In the area between Prudhoe Bay and Delta Junction, where the
gas pipeline will parallel the TAPS, the problems encountered during the
initial stages of construction may be compounded due to the presence of
animals, particularly bears, that were habituated to handouts and
garbage by TAPS activity. Some bears are known to have caused problems
after TAPS construction camps were closed, at abandoned camps, Alaska
Department of Transportation and Public Facilities camps and at TAPS
pump stations. Some of these animals were destroyed but others are
still active along the Haul Road. The influx of people into the cor-
ridor dul-ing preparation of camps and the initiation of construction
will be accompanied by the arrival of problem animals. This will occur
whether pipeline workers are exposed to a good ehvironmental briefing or
not. It is imperative that the initial approaches of these animals are
not rewarded with food derived from garbage and active feeding. These
animals must be discouraged at their first arrival and chased away.
The problem described above will occur most frequently between the
Yukon River and Galbraith Lake Camp, less frequently north of Galbraith
Lake Camp, and least south of the Yukon River. The segment of the
corridor between Delta Junction and the Canadian border should contain
only "naive" animals because the TAPS project did not follovv this route
and the Haines Pipeline and Alaska Highway were built too long ago to
expect any animals from that period to be alive yet. It is essential to
maintain a clean operation in all areas to ensure that carnivores in
contact with the construction project do not become accustomed to unnatural
food sources.
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Some of the recommendations that follow reflect the regional
differences in animal problems that can be expected along the NWA route.
The most difficult area will be between the Yukon River and Galbraith
Lake Camp. Tailoring deterrent programs to the anticipated severity of
animal problems is valid and justified. It emphasizes more effective
controls where they are needed and, in areas where fewer problems are
anticipated, permits a program involving less effort and less capital
expenditure. There is one aspect of an animal deterrent program that
cannot be regionalized and must apply throughout the route between
Prudhoe Bay and the Canadian border: ANIMAL FEEDING AND IMPROPER
FOOD STORAGE AND GARBAGE DISPOSAL MUST BE STRICTLY FORBIDDEN.
The following sections provide animal deterrent recommendations for
the NWA project. These recommendations are developed specifically to
reduce problems with bears, wolves and foxes. However, if followed
these programs should reduce problems with other potential mammalian
scavengers such as wolverine (Gulo aulo), mink (fvlustela vison), marten
(Martes pennanti) and ground squirrel (Spermophilus undulatus) and
scavenging birds such as ravens (Corvus corax) and gulls.
GENERAL ANIMAL DETERRENT RECOMMENDATIONS·
It is very important that NWA establish an animal control program
before construction begins. Initially this requires a commitment to
avoid establishing conditions that are attractive to scavenging animals.
A program of consistent and adequate garbage collection and proper and
adequate food storage is necessary to ensure that camps and construction
areas are kept free of exposed attractants. In addition, animal feeding
must be strictly prohibited. Immediate disciplinary action should be
taken against anyone feeding wild animals. Warnings against this
activity should be included in the Environmental Briefing that each
worker must attend before entering the field. The warning should
include reference to the state law which prohibits active feeding and
leaving food and garbage with the intent of feeding animals (5 AAC 81 .218).
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It should be clearly stated that in addition to state punishment for
this violation, NWA also prohibits this activity, actively enforces the
prohibition and disciplines any and all violations. NWA's disciplinary
action, whether loss of pay, job or other punishment, should be clearly
described so that workers entering the field know exactly what disciplin-
ary measures will be levied if they violate the prohibition.
Following this notification of intent to enforce the regulation,
violators should be promptly disciplined the first time. This policy is
for two reasons. Firstly, it establishes a precedent and announces to
other workers that NWA intends to stand by its commitment to minimize
animal problems and thereby protect the environment and the health and
safety of workers. Secondly, it is dangerous to reward animals with
food when they first approach NWA facilities and construction areas
because they will become habituated. Habituation is dangerous in the
long term because the animals lose their fear of man a little more each
time and eventually are quite bold in their scavenging and panhandling.
At this point NWA will have to deal with a serious problem that could
have been avoided. If the program is not firmly enforced from the very
beginning, NWA can expect animal problems to develop and recur through-
out the project.
A commitment to avoid or minimize the presence of animal attractants
on the NWA project must form the philosophical basis for NWA's animal
deterrent program. Taking firm disciplinary action against violators of
the animal feeding prohibition, constitutes one of the procedural
components of the program. Other procedural components include food
handling, garbage storage, collection and incineration, and inorganic
disposal. These aspects of an animal deterrent program can be supple-
mented with physical deterrents that will contribute significantly to an
effective program. The fo ll ovJi ng sections review recommended deterrents
for use on the NWA project.
RECOMMENDED ANIMAL DETERRENT FENCES
Designs, specifications and descriptions of fences recommended for
use at construction camps and compressor stations on the proposed NWA
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gas pipeline project are presented. Three fence designs, each repre-
senting different animal deterrent capabilities, are proposed. Dif-
ferent designs recommended for different sites reflect the degree of
carnivore, principally bear, problems anticipated at each .. These
designs and recommended locations are based partially on the densities
of animals along the right-of-way but are more closely tied to the
locations where TAPS experienced problems.
The designs and recommended locations presented here are for the 16
major construction camps and the seven compressor stations planned for
the initial phase of pipeline operation. They should not be haphazardly
recommended for other areas or facilities without a prior review of the
potential for animal problems. The intent of recommending three designs
specific to areas is to provide a cost effective fencing program, one
which neither overkills and, therefore, is more expensive than necessary
nor is inadequate, and thus will require a considerable amount of
additional animal control at camps.
The designs, specifications and other recommendations contained
herein are essentially the same as those previously submitted (Follmann
1980). However, they have been further refined and contain more complete
information and, therefore, supercede the previous report.
Site Recommendations for Fences
It should be reemphasized here that the fences are recommended for
specific camps assuming the camps will be maintained such that animal
attractants are eliminated or greatly minimized by proper food storage,
by an effective and consistent garbage storage, collection and incinera-
tion program and by prohibition of animal feeding activities. If these.
functions are not included in the NWA comprehensive animal control
program the fences recommended here may not be adequate in all cases and
the next highest design may be required. It would be a serious mistake
to assume that fences are a panacea and by themselves will eliminate all
problems.
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The TAPS construction experience strongly suggests that temporary
and permanent facilities located in certain areas north of the Yukon
River have a high potential for encountering animal problems, partic-
ularly with bears. An additional consideration is the Bureau of Land
Management (1980) plan to develop facility nodes near Five-Mile, Prospect,
Coldfoot and Chandalar Camps and just south of TAPS Pump Station 3.
These could add to the overall attractiveness of these areas for scaveng-
ing animals. The NWA sites planned in these areas should be enclosed
with above-standard-grade animal repellent fences.
Construction camps recommended for the highest grade animal repel-
lent fence are Five-Mile and Chandalar. These two areas had severe
black bear and grizzly bear problems, respectively, during TAPS con-
struction.
Old Man, Prospect, Coldfoot, Dietrich, Atigun and Galbraith Lake
Camps are recommended for the intermediate grade repellent fence. The
proximity of Compressor Station 7 to Prospect Camp and Compressor
Station 4 to Galbraith Lake Camp requires similar protection for these
sites. The intermediate grade fence at Compressor Stations 4 and 7
could be restricted to the area around the temporary construction camps
proper, rather than around the entire site. Since neither of these
compressor stations is planned as an Operation and Maintenance Site
during pipeline operation, they probably will be adequately protected
with the standard grade fence once the large construction work force is
reduced to the operation staff. Again, this assumes good maintenance
within the site boundaries to avoid attracting animals to the site.
Compressor Stations 5, 6 and 8 fall within this problem area but
are not planned for the initial construction phase. Therefore, fence
designs for these sites should be determined later based on the effective-
ness of animal control procedures utilized during the first phase of
construction.
Specific animal problems have not been identified between Delta
Junction and the Canadian border but the proposed Sears Creek Camp is
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located close to an area indicative of good grizzly bear habitat. It is
therefore possible that the intermediate grade fence may be needed at
this camp, although at this time the standard grade fence is recommended.
All other construction camps and compressor station facilities
should be adequately protected by the standard grade animal repellent
fence. However, should animal problems arise at these sites, they can
be relatively easily upgraded to the intermediate grade fence to in-
crease the fence's effectiveness.
The camp used at Delta during the construction of TAPS will be
reopened for the NWA project. The camp is already fenced with the
on-grade 8-ft chain link and barbed wire barrier used by TAPS. No
specific animal problems were noted at this camp (JFWAT files), and
there is no reason to believe that the situation will be different
during gas pipeline construction. Therefore, it is recommended that the
existing fence not be upgraded to the specifications proposed in this
report.
Facilities and recommended fence designs are summarized in Table 7.
Recommended Fence Specifications
Fence specifications for the high, jntermediate and standard grade
fences are presented separately. Front and end views of these designs
are illustrated in Figures 2 and 3.
Standard Grade Fence. Following are recommended specifications for
the standard grade animal deterrent fence suggested for use at the camps
and compressor stations identified in Table 7.
• 10-ft 2-inch-mesh chain link fence with 3 ft buried verti-
cally; place on outside side of posts.
•
•
9-gauge chain link material .
3-inch fence posts spaced at 10-ft maximum intervals. Corner
posts should be of 4-inch diameter and gate posts of at least
7-inch diameter. Posts can be set in concrete or in other
ways that ensure strength and stability.
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Table 7. Fence grade recommendations for NWA construction camps and
compressor station sites.1
High Intermediate Standard
Grade Grade Grade
5-~lile 01 d t'1an Happy Valley
Chandalar Prospect Franklin Bluffs
Coldfoot Prudhoe Bay
Dietrich Livengood
Atigun Sears Creek
Galbraith Lake Tok
Comp. St. 4 NorthvJay
Camp. St. 7 Comp. St. 2
Camp. St. 9
Comp. St. 11
Comp. St. 13
Comp. St. 15
1 Fence grades for Phase 2 compressor st~tions can be determined when
they are being planned for construction; use Phase I results to
determine grades.
~~~~~,.---
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HIGH
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---0
INTERMEDIATE
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Figure 2. Oblique view of recommended high, intermediate and standard grade animal deterrent fences.
Not to scqle.
-
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Ill C I I
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7 Gouge ---,J I --
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-I J;-. q~·· ~ .". . .. ,
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Tensiqn Wire-------.,,_ l .,
Grode _ . .J..... ... ~--·--·· -···r----~j:.'. ·· :;1
I
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·;,! '.:,:-:r::· / site specific
,··u~·: j
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I
7 GOUIJC
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Tension Wire~ .
--"'-Grode --.-'" ~:·:.. -~~~ -"-L-->.---~----
1 tj.' ~ j-
_f"(') ~·:· •. • _/~ .. (/ Depth 1s
j
to--}_ .. :! site specifiC
a_ ul j d (J . ~----~· ... ,(:1 I."·:··'·. I _______ _
Figure 3. End view of recommended high, intermediate and standard grade animal deterrent fences.
Not to sca1e.
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3 strands of barbed wire (double strand 12-l/2 gauge; 4-point
barbs on 5-inch centers) at top of fence angled outward.
• 7-gauge top, bottom and two intermediate tension wires.
• 3/8-inch truss rods.
o all tension bars, fasteners, etc. should be of steel, not
aluminum.
Intermediate Grade Fence. Following are recommended specifications
for the intermediate grade animal deterrent fence suggested for use at
the camps and compressor stations identified in Table 7.
1 10-ft 2-inch-mesh chain link fence with 3ft buried verti-
cally; place on outside side of posts.
1 9-gauge chain link material.
• 3-inch fence posts spaced at 10-ft maximum intervals. Corner
posts should be of 4-inch diameter and gate posts at least
7-inch diameter. Posts can be set in concrete or in other
ways that ensure strength and stability.
•
3 strands of barbed wire (double strand 12-l/2 gauge; 4-point
barbs on 5-inch centers) at top of fence angled outward.
7-gauge top, bottom and two intermediate tension wires.
3/8-inch truss rods .
• all tension bars, fasteners, etc. should be of steel, not
aluminum.
•
at 1 ft and 5-6 ft above ground level, one strand of elec-
trically charged wire should be bracketed to outside of fence
about 10 inches away from the chain link fence.
the two electrical wires should be charged independently with
chargers yielding high voltage and low amperage (see recom-
mended specifications below).
• electrical wires should be charged (+) and the chain link
grounded(-).
High Grade Fence. Following are recommended specifications for the
high grade animal deterrent fence that is suggested for use at Five-i1ile
and Chandalar Camps.
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10-ft 2-inch-mesh chain link fence with 2 ft buried verti-
cally; place on outside side of posts.
4-ft width of the same grade chain link fence laid horizon-
tally dn the outside of the fence at a depth of 2-ft and
hog-ringed to the bottom of the vertical fence; backfilled
with pad material.
i 9-gauge chain link material.
e 3-inch fence posts spaced at 10-ft maximum intervals. Corner
posts should be of 4-inch diameter and gate posts at least
7-inch diameter. Posts can be set in concrete or in other
ways that ensure strength and stability.
3 strands of barbed wire (double strand 12-l/2 gauge; 4-point
barbs on 5-inch centers) at top of fence angled outward.
o 7-gauge top, bottom and two intermediate tension wires.
1 6-gauge hog-rings (not aluminum) spaced at 1-ft intervals to
connect horizontal and vertical fence materials.
•
3/8-inch truss rods.
all tension bars, fasteners, etc. should be of steel, not
aluminum.
at l ft and at 5-6 ft above ground level, one strand of
electrically charged wire should be bracketed to the outside
of the fence about 10 inches away from the chain link fence.
the two electrical wires should be charged independently by
chargers yielding high voltage and low amperage (see recommended
specifications below).
electrical wires should be charged (+) and the chain link
grounded (-).
General. Recommendations for construction of chain link fence
presented here assume that the standard techniques of using braces,
truss rods, .etc. at corners and pull posts, and hanging and stretching
fence on posts will be used. The specifications provided here are only
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intended to make the fence more secure against animal intrusion and do
not include standard fence construction procedures and techniques.
If sites recommended for the standard grade animal deterrent fence
encounter animal problems that stress the fence, remedial action can be
taken by upgrading the fence to the intermediate grade. This requires
only the addition of electrification.
Electric Fence
The electric fence is recommended to supplement the chain link
fence in areas where significant to moderate bear problems are expected
to occur based on the experience during TAPS construction and operation
(see preceding section in this report). The review of fences as deter-
rents (see preceding section in this report) clearly indicated that
either electric fences or electric fences that supplement physical
barrier fences are necessary to provide protection against bear intru-
sions. Purely physical barriers would not be adequate unless designed
to extreme specifications. These would be unnecessarily difficult and
expensive to build for NWA construction camps and compressor stations.
Wire. The wire used for the electric fence should be barbed. It
has been suggested by various authors, a~ reviewed in a preceding
section of this report, that the barbs will penetrate into the heavy fur
of the animals and thereby increase the probability of effectively
shocking an intruding animal. Unless the animal is shocked and deterred,
it will continue to test the fence and perhaps damage the electrical
installation and/or the chain link.
Barbed wire is more difficult to string than smooth wire. In
addition, it appears that it requires more tension to maintain its
tautness than smooth wire. This could be a problem along the pipeline
corridor.where extremes of temperature occur. In particular, at temper-
atures far below zero the metal may become brittle and be subject to
breakage at high tensions. A smooth wire fence strung at lower tension
perhaps would be more suitable. The more powerful fence chargers that
are available may eliminate the need for barbs.
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Electric Wire Deployment. Two approaches have been shown effective
in overcoming the problem of an animal not being adequately grounded
when in contact with a charged wire: alternating charged (+) and ground
(-) wires and placing wire mesh attached to the charger ground terminal
so that an animal is standing on it when in contact with the charged
wire. Neither approach is desirable for NWA camps. A series _of (+) and
(-) wires sufficiently close to insure simultaneous contact to a height
of 5 to 6 ft would be costly and require considerable maintenance. A
horizontal mesh on-grade would be covered by snow much of the year and
thus be insulated from an animal, particularly the canids which are
active throughout the year. In addition, it would increase the proba-
bility of shock to workers.
A workable solution is to suspend only chaiged (+) wires on the
outer side of the chain link fence and to attach the chain link fence to
the ground (-) terminal of the charger. To be effective the brackets on
which the charged (+) wires are suspended must be of non-conductive
material. Any animal that attempts to penetrate the fence by climbing
over or going through, by design, will have to be in contact with a
charged (+)wire and the chain link thus ensuring a good shock. This
design also reduces the probability of a. person being shocked.
The two electrical wires should be independently charged with two
fence chargers. Therefore, if one wire is grounded or broken the other
will still be charged. The lower wire should deter canids and bears
that investigate or attempt t6 dig under the fence. The upper wire
should be placed at 5 ft above ground if black bears are present or 6 ft
if the larger grizzly is present. The upper wire should deter bears
standing upright or animals attempting to climb the fence.
Chargers. NWA should use only commercially available chargers to
energize electric fences. These have been developed over a period of
years, are effective and are safe to use. Gunson (1980 pers. comm.),
who has considerable experience with black bears and who designed a
portable electric fence for black bears (Wynnyk and Gunson 1977),
recommends chargers manufactured by Bake~ Engineering Enterprises Ltd.
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(Edmonton, Alberta, Canada) and by Gallagher Electronics Ltd. (Hamilton,
New Zealand). These high power chargers would be effective against
bears.
The Baker charger operates at 5000+ volts and 1 amp with a pulse
width between 75 and 250 microseconds (Boswell 1980 pers. comm.). This
short pulse width permits safe operation at these high voltage and
amperage· 1 eve 1 s. Bosv.Je 11 ( 1980 pers. comm.) indicated that Underwritel~s
Laboratories requires a pulse width of 300 microseconds or less for
safety using these voltage and amperage levels. The chargers, there-
fore, are safe to use and the high power developed during the pulse is
quite effective as a deterrent.
Specifications have not been obtained on the Gallagher charger.
Other chargers described in studies of electric fence effectiveness have
used voltages ranging from 5000 to 12,000 volts and 0.015 to 0.1 amp
(Table 6). With high voltages it is essential to maintain low amperage,
unless the pulse width can be shortened as with the Baker charger. The
higher power developed by the Baker charger should provide a better bear
deterrent than the power developed by a standard livestock charger.
Most studies have shown that a pulse rate of about 60 per minute is
suitable. Slower pulse rates leave too much time between shocks and a
faster rate uses more energy than necessary for deterrence.
Both AC and DC chargers are available. At camps 110 volts AC could
be used to energize the fence but a DC charger using i2-volt batteries
(not 6 volt) would be more flexible. In this case the batteries could
be charged with AC line voltage. The AC charger is probably the best
choice since it would reduce the amount of maintenance necessary. An
extended power outage that coincides with a period of nuisance animal
activity could pose a problem. With proper safeguards, however, this
should not be significant. Animals that have already experienced a
shock, will be less prone to test the fence during a short outage.
Bears have been reported to test fences periodically, however, and
outage durations should be kept to a minimum.
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Safety. An electric fence will shock a person as readily as a
wild animal. The commercially available chargers are safe. They are
used throughout the country on farms, ranches and other areas, even
where children are present. The shock is unpleasant but harmless. The
more powerful chargers described above will provide a stronger shock but
the specifications of the chargers are within established criteria for
safety.
Although many workers will live in camps most of the activity
occurs within the perimeter fence and not outside of it. The chain link
fence will not shock a person who comes in contact with it even though
it is connected to the ground (-) terminal of the charger. The charged
(+) wires are suspended 10 inches out from the outside of the chain
link, beyond the reach of anyone on the inside.
A person suitably grounded will be shocked when in contact with
the electric wires. This is unavoidable. It is essential that signs
identifying the fence as being electrified be hung on the outside of the
chain link at regular intervals. A suggested interval might be every
other 10-ft section. This is considerably more frequent than normal but
may be justified in this application. These signs are commercially
available and should be installed before the electrical wires are
energized.
Any time work is conducted on the camp pad beyond the fence perimeter,
such as for maintenance, the electric fence can be turned off. This is
not difficult and will prevent accidental shocks. The current should be
switched on immediately afterward, however, for a bear could easily
damage the wires if it is not shocked.
Fence Operation. The charger units should be housed in the gate
shack so that the attendants are in control of the fence. The attendants
should know how to use the on/off switch and ensure that the charger is
connected to 110 volts AC camp power. If DC units are used, they should
check the batteries, replace expended batteries and charge used batteries.
The attendant should check the voltage in the wire with commercial units
made specifically for this task. It would be good procedure to check
fence voltages at shift changes or at least once each day.
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During the period when bears are out of dens (determined site
specifically in spring and fall by the occurrence of bears or their
sign), both electric wires should be charged at all times. During late
fall, winter, and early spring the top wire can be turned off because
the overhanging barbed wire will probably be adequate to deter any
canids from climbing over the fence. The lower wire should be charged
until snow covers it, thus grounding it. At this point the presence of
snow cover, frozen pad material and the buried fence will deter digging.
When the fence is first charged each year, the charged (+) wires
SHOULD NOT be baited as suggested by several authors (see revievJ in
preceding section). It would be a mistake to attract any bear in the
vicinity to the fence because some might not approach without bait.
However, once a bear begins to frequent the area it would be appropriate
to suspend a bait on a post to attract the animal and ensure a good
shock. Once shocked the animal will probably leave and the bait can be
removed. The bait should be placed so the bear in its attempt to
obtain it will simultaneously contact the charged (+) wire and the chain
link or posts (-), in case the gravel pad is insulating the bear from a
ground.
When work is required on the outside of the fence the charger
should be turned off to prevent accidental shocks. This will only
ential notification of the gate attendant. When the work is completed
the attendant should be notified and the fence turned on. This pro-
cedure is quite simple and entails only communication between the work
crew, camp manager and gate attendant.
Gates
Gates represent an unavoidable weak point in an animal deterrent
fence. This is particularly the case where the gates experience a great
deal of traffic as in a pipeline construction camp. The solution
appears to be more procedural than physical.
Two types of gates are feasible for use at construction camps and
compressor stations. They are: a standard 2-leaf swinging gate and a
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single unit sliding gate. The latter type is used at TAPS pump stations,
and is remotely operated by a gate attendant. A major disadvantage of
these gates, at least as used on TAPS, is that there is about a l-l/2 ft
space between the ground and the bottom of the gate to allow for snow
accumulation in winter. Even when closed this gate will not deter a fox
or wolf and perhaps would allow black bears and small grizzly bears to
penetrate. A comment made by the gate attendant (unidentified), at TAPS
Pump Station 8, who worked at TAPS construction camps, was that the
remote control mechanism would not be sufficiently durable to handle the
opening and closing required for the traffic volume at a construction
camp. He felt that a manually operated gate would be more reliable and
trouble-free.
As suggested above, the solution to the gate problem is procedural.
Either a sliding or 2-inch-mesh double-leaf chain link swing gate should
be used and be manually operated, unless a durable remote control mech-
anism is commercially available. The gate should not have a clearance
exce~ding 4 inches. This will require regular maintenance of the gate
area to ensure clearance during snow conditions.
The gate should have a full-time attendant who will be responsible
for maintaining proper function of the gate. During peak use hours the
gate can be left open to accomodate traffic. During non-peak hours the
gate should be kept closed and only opened to permit passage of individual
vehicles. Any time an animal is in the vicinity (within 100 yards) of
the gate and demonstrating interest in entering the camp, the attendant
should be prepared to close the gate and implement a contingency plan to
drive off the animal.
A minimum 12-inch square timber should be buried at ground level
between the gate posts to deter digging beneath the gate. If desired, a
concrete sill can be used instead of a timber but it may be more subject
to cracking from traffic loads.
At camps using supplementary electrical fences it will not be
necessary to place electrical wires across the main gate(s). However,
at auxilliary gates located in other areas of the camp, electrical wires
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should be strung across them using plastic gate openers. These gates
should be kept closed at all times except when emergencies or main-
tenance require their use. Auxill iary gates should be protected with a
buried 12-inch square timber between the gate posts, and the clearance
between the timber and bottom of the gate should not exceed 4 inches.
CONTROL OF PROBLEM ANIMALS
Conscientious solid waste disposal, fencing of camps and compressor
stations, and strict enforcement 9f no feeding regulations should do
much to minimize or prevent many carnivore problems. Habituated animals
already inhabit areas to be traversed by the NWA project, however, and
preventive measures will not ever be completely effective. Therefore,
the question of providing for the control of problem animals must be
addressed.
It is important that NWA employ an experienced biologist capable
of, and responsible for, handling animal problems. This will help
ensure consistency in administering a standard animal control policy
while providing the flexibility necessary to handle situations on a case
by case basis. This individual should keep records on control actions
and act as a liaison with agency personnel. He should also ensure that
prompt action be taken whenever problems occur in order to avoid a
gradual buildup of more serious situations. He should also be sure that
a lack of incidents does not result in a slackening of preventive
efforts.
The NWA project should obtain two portable culvert traps. One of
these should be kept north of and one south of the Yukon River. These
traps are typically 3 x 8 or 4 x 8 ft sections of culvert with l/2 x l/2-
inch steel mesh over one end and either a guillotine-type or swinging
door attached to a trigger mechanism on the opposite end (Rutherglen
1976; California Dept. of Fish and Game 1965). The ADF&G and Alyeska
Pipeline Service Company have had culvert traps made in Fairbanks (Buhite
1980 pers. comm.). These traps should be used to capture and transport
problem bears from areas of human activity.
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Suggested Guidelines
Although it is possible to suggest some general guidelines, there
are no hard and fast rules for handling all carnivore/human problems.
In emergency situations where carnivores threaten life or property no
prior authorization is needed to kill the problem animal. However, if
the incident is precipitated by feeding or improper garbage disposal the
person is liable for killing the animal. Game taken in defense of life
or property is the property of the state. For non-emergency situations,
decisions must be made on a case by case basis at the discretion of the
control officer within the framework of applicable state and federal
regulations. The following sections contain points to consider with
regard to animal control.
Canids. Problems with foxes, coyotes and wolves can, in most
cases, be handled in a similar manner. When a problem involving canids
arises the nature of the problem must first be determined. In the case
of an animal exhibiting abnormal behavior, sickness, or aggression
resulting in bites or attempted bites, the animal should be destroyed
and the head salvaged and sent to the Virology-Rabies Unit in Fairbanks
to test for rabies. If the animals are non-aggressive and merely
present, the source of attraction (inadequate garbage disposal Ot'
handouts) should be eliminated to disperse the animals. If it is not
possible to remove the attractant or if the canids continue to frequent
the area, other methods are justified. Relocation of canids is not
recommended, however. ADF&G must be contacted tu get permission to use
deterrents or harrassment techniques. If canids do not pose actual
health and safety problems they should not be dispatched.
Bears. When a bear problem is reported it is necessary to evaluate.
whether the presence of the bear alone has precipitated the complaint or
whether a real hazard to life or property exists. If artificial food
sources have caused or aggravated the problem they must be eliminated
immediately. The longer bears are permitted to utilize artificial food
sources the more habituated and incorrigible they become. Before
proceeding with any action (other than emergency defense of life or
property) permission must be obtained from ADF&G.
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The most appropriate action when bears continue to loiter in the
vicinity of human activity would be to use a deterrent to elicit avoid-
ance of an area or a food source. Lacking this, with clearance from
ADF&G and the U.S. Fish and Wildlife Service, the next best choice would
be to attempt harassing bears with a helicopter, chasing them away from
the problem area in hope that the stress would cause them to avoid the
vicinity in the future.
Translocating problem bears is a generally unsatisfactory approach
due to the expense involved and the ability of bears to return even over
long distahces to the vicinity of their capture. There are, however,
certain circumstances when translocation should be considered as an
option if deterrents and helicopter harassment fail. Translocation must
be evaluated on a case by case basis taking into consideration the sex
and past history of the bears involved.
Considering the expense (to be borne by N\.·!A) and the probability of
success, it is evident that translocation must be a selective tool. It
is probably most appropriate to move female grizzlies with cubs of the
year and young age grizzly bears. In the case of female grizzlies with
cubs the entire family group should be moved. However, it would also be
worthwhile to consider breaking up the family group of an aggressive
female with older offspring by translocating her 2-year-or 3-year-old
young. This could reduce the threat from the adult (who would probably
be less aggressive without young) without removing a breeding female
from the area. In addition, young age bears may be less likely to
return to the place of capture. The main objective of a bear control
program should be, whenever possible, to protect female grizzlies because
they are the productive segment of the population. Generally, the ADF&G.
policy is to not transplant bl~ck bears although in the case of a troublesome
female with cubs it might be considered.
If bears can be captured in culvert traps and transported without
drugging, it is preferable. It would be useful to mark them even if
only with peroxide or paint in order to detect any returns. Bears
should be moved at least 100-150 miles to increase the probability of a
successful translocation.
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Destroying bears should be a last resort not only because of
adverse ecological impacts but because of potentially negative public
response. There are a number of situations, however, where killing a
problem bear is appropriate. These include cases of very aggressive
bears that, though unprovoked, threaten or attack people (this does not
include females defending young or bears defending a carcass, for
example), bears that cause extensive property damage, visibly unhealthy
or senile individuals, incorrigible black bears and male grizzlies, and
nuisance female _grizzlies after two or three unsuccessful attempts to
translocate them. In any of these situations careful judgment of the
control officer is needed. The most important bears to avoid killing
are productive female grizzlies. These and young age grizzlies should
be considered for relocation as mentioned previously.
It is important to act promptly and to address problems as they
occur. If a dangerous situation develops it is neither in the best
interests of the bears nor the project to avoid taking necessary action.
Once again, this does not apply to the case where a bear is merely
present. When truly hazardous conditions exist, however, a well-meaning
but misguided attitude of looking the other way to protect an individual
bear may in the long run do more harm than good.
RECOMMENDED ENVIRONMENTAL BRIEFING TOPICS
An Environmental Briefing for all NWA pipeline workers is required
by Stipulation 2.1 (see previous section in this report). This stipula-
tion requires that all workers be informed of environmental concerns
along the pipeline corridor and of the ways that NWA intends to minimize
problems. This should be a broad-spectrum briefing entailing subjects
from permafrost and spawning beds to garbage disposal. The following
topic outline includes those subjects relevant to carnivores along the
NWA pipeline corridor that should be included in the environmental
briefing developed by NWA.
• Introduce workers to grizzly bears, black bears, wolves, red
foxes, and arctic foxes (both summer and winter pelage) with
color slides.
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Provide general information on distributions of these animals
along the pipeline corridor. Also, sensitive periods such as
denning, breeding and rearing of young, and critical areas
such as floodplains for grizzly bears in the spring, should be
identified.
A general review of bear behavior should be included to
identify types of animals that are most dangerous (for example,
females with cubs and bears guarding kills), situations that
could lead to attack, and the nature of charges. Stress
avoiding these situations and how to minimize the probability
of an attack.
Stress the physical danger from bears and wolves and the
disease and parasite danger from wolves and foxes. Augment
with color slides of property damage and maulings caused by
bears. Identify the need for inoculations when bitten and
stress that even contacting a suspected rabid animal may
necessitate treatment. Also explain that rabies is usually
fata 1.
Feeding these animals is prohibited by the Alaska Department
of Fish and Game (5AAC 81.218 Feeding of Game). This includes
leaving food or garbage on the ground with intent to attract
animals. Identify that NWA policy entails termination of
anyone actively feeding animals or leaving food or garbage
with the intent of attracting animals.
Garbage and other solid and liquid wastes must be disposed of
promptly and in approved containers.
Harassing animals with motorized vehicles and airplanes is
prohibited by state (5AAC 81.120 General Provisions) and
federal (16 U.S.C. 742 (a)-754. Fish and Wildlife Service.
742 j-1 Airborne Hunting) regulations. In addition, dis-
turbing dens is prohibited (5AAC 81.090. Fur Animals); this is
significant because all carnivores use dens in some phase of
their annual life history.
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Harassing or killing animals is permitted in defense of life
and property (5AAC 81.375. Taking Game in Defense of Life and
Property). However, this does not apply if the nuisance is
caused by improper garbage disposal or by some other attractant.
The workers should be informed as to the state and federal
regulations regarding hunting, fishing and trapping in the
areas traversed by the pipeline corridor.
NWA intends to build and operate the proposed gas pipeline
with as little damage to the environment as possible. Commit-
ments to this effect have been made to the government and to
the public. These commitments can only be met with everyone's
cooperation. It is each individual's responsibility and
mandate to adhere to these regulations and to company policies.
Violation of these rules will result in job termination.
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RECOMMENDATIONS FOR ADDITIONAL
STUDY OF ANIMAL DETERRENTS
The animal problems that will occur during construction of the
proposed NWA gas pipeline project primarily involve attraction of bears
and canids to unnatural food sources consisting of garbage and handouts.
These problems can occur throughout the pipeline route. The previous
section on recommendations consisted of fencing and translocation and
dispatch of problem animals. Strict enforcement of the no-feeding
regulation and fencing at construction camps and compressor stations
will eliminate or greatly minimize animal problems as long as the fences
and gates are properly operated and maintained and the facilities are
kept as free as possible of garbage and other attractants.
Translocation and dispatch of problem animals are recommended if
animals have not been deterred and/or have met the criteria established
in the preceding section for these remedial actions.
·prevention of animal problems along the right-of-way other than at
camps, is more difficult since fences are inappropriate. The state-of-
the-art of other animal deterrents is not adequate for us to recommend
that any or all should become a part of ~WA 1 s animal control problem.
However, some have potential merit should additional information be
obtained. Inclusion of one or more of these techniques in NWA 1 S animal
control program could enhance the program 1 s effectiveness throughout the
741 mile route, not just at the points represented by camps and compressor
stations. The purpose of this section is to identify additional studies
on the more promising approaches that have been reviewed in preceding
sections of this report. Recommended studies are as follows:
1. Tests of the effectiveness of commercially available and other
noxious chemical deterrents should be conducted under controlled
conditions on bears and representative canids. Captive arctic
foxes, red foxes, wolves, black bears and grizzly bears are avail-
able in the Fairbanks area for these experiments. The controlled
tests should be conducted in both summer and winter to determine
93
the temperature lability of test compounds. Favorable results
should then be applied to limited field tests.
The application of these materials to garbage bags, garbage
containers and other food and garbage storage facilities could be
important as part of the animal control program. An effective
garbage removal and storage program prior to incineration will
entail use of bags and other containers. Bears and canids will be
attracted to and perhaps destroy these containers scattering the
contents thus, in part, hindering NWA's concerned effort to main-
tain a clean project. These deterrent compounds could eliminate
this possibility and thereby greatly enchance NWA's garbage removal
and clean-up program. Treatment of containers and storage facil-
ities would be a significant supplement to the garbage handling and
food storage program.
2. A logical systematic approach should be taken to develop emetics as
aversive conditioning agents in carnivores along the NWA corridor.
Carnivore species likely to be involved in man-carnivore inter-
actions should be fed emetics under controlled conditions in the
laboratory. Several species (arctic fox, red fox, wolves, black
bears and grizzly bears) are available for this type of study in
the Fairbanks area.
After proper dosage and dissolving rates are established for
each species, the study would be expanded to controlled field
situations. Food similar to that which would be available to
carnivores during NWA pipeline construction would be used and by
monitoring marked animals (preferably radio-collared) the degree of
aversion could be determined. Animals may return to natural food
hunting patterns or may learn other methods to avoid baited foods
in which case baiting procedures should be modified.
The use of emetics on the NWA project would be in field
applicqtions along the right-of-way. If animals are attracted to
work sites by garbage, litter and handouts, they should be deterred
from continued approach to the right-of-way. Application of
emetics to baits consisting of scraps of garbage or food could
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condition the animals to avoid these foods. Emetics could provide
a relatively inexpensive and useful technique to handle problems
and could reduce the need to kill nuisance animals.
Noise deterrents should be tested in the field to determine their
effectiveness on the species of concern. These experiments could
be conducted on an opportunistic basis where problem animals occur,
but probably would be more conclusive where animals already concen-
trate such as at existing dumps.
Noise deterrents could supplement NWA's animal control program
when other techniques are unsuitable or ineffective. For example,
a noise deterrent could be used at camp gates to deter approaching
animals. This technique would be controlled by the gate attendent.
The amount of time that the gates need to be kept closed could be
reduced and the need to close the gates during peak traffic at the
approach of a potentially troublesome animal could be eliminated.
Noise deterrents might also apply to work sites along the right-of-
way, reducing work stoppages due to nuisance animals. Portable
noise generators would add flexibility to a control program and be
useful where animals occasionally pose problems at remote locations
along the route.
Two criteria regarding field ~tudies are important to consider.
Field studies north of the Yukon River should be conducted on opportun-
istic bases where problem animals can be used. Baits should not be used
in this area because of the presence of "experienced" animals. AllovJing
these and "naive" animals to become habituated to artificial food
sources for purposes of experimentation could cause problems later.
Secondly, field tests of emetics should be conducted where animals are
already using artificial food sources or, if animals must be baited,
these experiments should be conducted away from the pipeline corridor.
This will help avoid habituating animals to artificial food sources in
the vicinity of future construction activities.
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vJe strongly recommend that these three studies be considered by
NWA. Favorable results could significantly increase the effectiveness
of both the food storage/garbage disposal and animal control programs.
No matter how concerned and effective the NWA policy is in maintaining a
clean project and preventing animal feeding, some problems will still
occur. Bears and canids are curious opportunists readily attracted to
food and garbage odors and to new sources of food. Potential nuisance
animals are always present and ready to take advantage of any lapses in
preventative programs. Non-lethal means of discouraging such behavior
could strengthen NWA 1 s animal control program.
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LITERATURE CITED
Alaska Department of Fish and Game. 1979. Hunting regulations. No. 20.
73 pp.
Alexander, W. 1968. Some harmful effects of noise. Canadian Medical
Association Journal, 99:27-31.
Allen, C. H., H. Frings and I. Rudnick. 1948.
of intense high frequency airborne sound.
Society of America, 20:62-65.
Some biological effects
Journal of the Acoustical
Alt, G. L. 1980. Bears, beehives and beekeepers. Gleanings in Bee
Culture, March:l37-l38, 162.
Alt, G. L., G. J. Matula, F. W. Alt and J. S. Lindzey. 1977. Movements
of translocated nuisance black bears of northeastern Pennsylvania.
Transactions of the Northeast Fish and Wildlife Conference, p. 119-
126.
Ames, D. R. 1978. Physiological responses to auditory stimuli. In:
Effects of Noise on Wildlife. Academic Press, Inc., New York.
305 pp.
Andrews, R. D. 1964. Effects of teargas on some animals. Journal of
Mammalogy, 45:321.
Anonymous. 1970. How to avoid being stung by b~ars. ·Province of
Manitoba Dept. of Mines and Natural Resources.
Anonymous. 1973. Scientists deter coy6tes with toad-tasting sheep.
Blue Jay 31:45-46.
Anonymous. 1977a. Station studies coyote-proof fence. National Wool
Grov1er, 67:22.
Anonymous. 1977b. New electric fence looks coyote-proof. National
Wool Grower, 67:29.
Anonymous. 1977c. Tabasco sauce repels coyotes. National Wool Grower,
67:21.
Ark, P. A. and W. Parry. 1940. Application of high frequency-electro-
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