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ALASKA DEPARTMENT OF FISH AND GAME
JUNEAU, ALASKA
G R 0 U N D T R A C K I N G 0 F A R C T I C
GRIZZLY BEARS
By Spencer Linderman
STATE OF ALASKA
HABITAT DIVIS ION -UBRAIY
A r.ASKA DEPA RTM ENT ...Qf FISH & GAME .,
William A. Egan, Governor 383 RASP BERRY ROAD
AN':HORAGE/ ALASKA 995 18 -1599 DIVISION OF GAME
Frank Jones, Director
Donald McKnight, Research Chief
DEPARTMENT OF FISH AND GAME
James W. Brooks, Commissioner
Final Report
Federal Aid in Wildlife Restoration
Project W-17-6, Job 4.12R
(Printed October 1974)
State:
Cooperators:
Project No:
Job No:
Period Covered:
FINAL REPORT (RESEARCH)
Alaska
Spencer Linderman, Harry Reynolds and Renewable Resources
Consulting Services, Ltd.
W-17-6
4.12R
Project Title: Big Game Investigations
Job Title: Ground Tracking of
Arctic Grizzly Bears
July 1, 1973 to June 30, 1974
SUMMARY
A mature male grizzly bear was immobilized May 10, 1973, fitted
with a radio transmitter collar and followed from the ground and from
aircraft until June 18. Visual contact with the bear was maintained,
whenever possible, at distances of 0.5 to 1.0 miles. The radio collar
seemed to be a minor but constant irritation.
Aircraft did not usually produce a strong response by the bear
unless they passed within about 500 feet. Observations of feeding
indicated the bear ate mostly grasses, sedges and overwintered berries.
The bear also ate remains of caribou killed by wolves. Analysis of
activity patterns showed that feeding was the predominant activity for
morning-midday, while resting and traveling predominated for evening-
night. During the period of observation the marked bear ranged over a
27-mile length of the Canning River and a 4-mile section of a major
tributary. Breeding behavior was observed and described. Ground tracking,
with the aid of a radio transmitter, is considered technically feasible,
but demanding.
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Summary • • •
Background .•
Objectives.
Procedures.
Results . • •
CONTENTS
Behavioral Effects of Collar and Trackers.
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1
2
2
2
3
4
5
Aircraft and Bear •••.... o •••••
Feeding and Food Habits.
Resting. • . . • .
Traveling. . . . . . • .
Breeding Behavior o • • • • • • •
Interactions with other animals ..
Movements • • . .
Activity Patterns . . • • • •
General Comments. . • • • • •
Acknowledgments . •
Literature Cited. • .
BACKGROUND
• • • • 6
6
7
. • . • . . 11
. . 11
16
• • • 17
• • • 17
Iri April 1972 a two-year study (originally under Job 4.0 S&I) of
Arctic grizzlies (Ursus arctos) was initiated in the Canning River
drainage of the eastern Brooks Range conducted jointly with Renewable
Resources Consulting Services, Ltd. This firm was conducting ecological
surveys for the Arctic Natural Gas pipeline
The study was divided into two parts:
capture and mark every bear in the drainage
by aerial resightings and 2) 24-hour ground
This is a report on the second objective.
OBJECTIVES
consortium.
1) a widespread effort to
to determine movement patterns
tracking of a single individual.
Twenty-four hour per day visual ground tracking of a single adult
male grizzly bear from spring emergence to fall denning to determine:
1.
2.
3.
4.
5.
Daily and seasonal movements,
Diurnal and seasonal activity patterns,
Food habits,
Seasonal use of plant communities,
Behavioral reactions to human disturbances, especially aircraft,
and
6. Denning behavior.
These objectives were only partially attained because of early
termination of this part of the study in mid-June.
1
PROCEDURES
A 14.5-year-old, 350-pound, male grizzly, named Z.B., was drugged
and captured on May 10, 1973 in the upper Canning River, Brooks Range,
from a FH-1100 helicopter using Palmer Cap-Chur equipment and sernylan
at 0.75 mg per pound body weight. He was fitted with a 2 1/4-pound
radio transmitting collar of 1 1/4-inch flexible vinyl tubing, with a
battery pack and transmitter located underneath his chin. Alternating
red and yellow Saflag streamers, 2 x 6 inches, were attached to the top
of the collar, behind the head, as an aid in maintaining visual contact,
and to avoid having the bear chased and recaptured again by the tagging
crew, which continued to work in the study area.
On May 14, a two-man crew began maintaining visual contact with the
bear 24 hours per day. Seven days tracking, two days off and seven days
tracking was the schedule attempted. Long Arctic days permitted the 24-
hour visual contact.
No attempt was made to get closer than 1/2 mile from Z.B. and
distances usually ranged from 1/2 to 1 mile. Observations were made
through binoculars and a 20-45x variable spotting scope. The two people
worked in shifts, maintaining watch when the bear was sleeping as well
as when awake. The tracking and observations were intended to be entirely
by sight as much as possible. A radio was only used as an aid when Z.B.
could not be seen during snowstorms, heavy ground fog, rain or when he
was in dense willow thickets.
Lightweight backpacking gear permitted the observation camps to be
moved on short notice as Z.B. 's movements dictated. All camps and
observation points were placed high on mountainsides to reduce the
chance of variable winds carrying our scent to Z.B. and unnaturally
affecting movements. No wood fires were built.
Two antennas were used in tracking. A high gain, straight wire,
dipole attached from tail wheel to wing strut of the aircraft was used
to pick up the radio signal when relocating Z.B. after the two-day rest
periods. A 12-inch, hand-held loop antenna provided greater directional
and close range sensitivity once the general area was located, and was
the only antenna carried for ground tracking. The dipole had approximately
10-15 miles range and the loop was useful to 2-3 miles.
A small HF band "handy talky" radio and antenna were carried to
report changes of location. Detailed field notes were recorded throughout
the effort. During periods of substantial activity one person often
recorded while the other observed. Remains of kills upon which Z.B. fed
were examined to determine species, sex and age of the animals. Feces
and vacated grazing areas were also examined to supple-ment feeding
observations. Daily movements were plotted on one inch: a mile maps.
RESULTS
Behavioral Effects of Collar and Trackers
Efforts to reduce disturbance of Z.B. by our presence were apparently
successful. Only once did our presence visibly affect him and that was
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when the helicopter inadvertently set us down too near him on a mountainside
after attempts to pinpoint his location by radio had failed. Variable
mountain wind currents carried our scent to him and he hastily departed
over the snowfields on top of the mountains.
The relatively light 2 1/4-pound radio collar caused no damage to
Z.B. Upon its removal June 17, after a malfunction, not only were there
no skin abrasions or lesions, but the neck hair under the collar was not
rubbed, broken or even matted. Presence of the collar precipitated
visible reaction, however, especially in the first week after collaring.
Z.B. would stop to shake his head and shoulders momentarily several
times per hour when he was active. This behavior appeared to decrease
somewhat with time.
Z.B. also rubbed his neck against the tall riparian willow bushes
and even on the ground and rocks, though these were rare occasions. It
was obvious that not all these reactions were precipitated by the collar
alone since he frequently rubbed and scratched the rest of his body,
especially the back, and sometimes the neck area was excluded altogether.
A dextrous maneuver seen on several occasions was Z.B.'s ability to
stand with his back to a clump of willows, reach above his head with a
foreleg, bend a branch down across his neck and shoulder, and rub his
neck against the branch held in that manner. This action seemed specifically
aimed at the neck-collar area. Z.B. was also eating willow buds occasion-
ally during this period and, at first, we thought he was merely stabilizing
himself in an upright position with his back against the bushes while
reaching up and pulling down the ends of branches for their buds.
Although he did eat willow buds, further observations showed that he was
specifically scratching himself at least some of the times.
Another apparent method of scratching was walking directly over a
tall, but limber willow stem so that it bent horizontally and scratched
the belly from front to rear as Z.B. walked over. In passing willows,
Z.B. would also lift his chin up and to the side, catch a branch under
his chin, then lower his head to trap the branch and "strip" it under
his chin and neck as he continued to walk. Although this behavior could
have been associated with examining the ends of branches for buds, it
appeared primarily used for rubbing on the head and neck.
These various activities were not associated strictly with the
presence of the collar, for during the short time Z.B. was under observa-
tion without a collar, he rubbed his chin and side of his face against
willows and purposely sidestepped over willows so he could walk over
them bending them beneath him fore and aft to rub on them.
In summary, we do not believe the collar was a major irritant and
that it did not significantly affect behavior. It was apparently a
rather constant minor irritation, however.
Aircraft and Bear
Five helicopter and six fixed-wing aircraft flights were recorded
with simultaneous observations of Z.B. No aircraft flights occurred
3
when other bears were under observation. In general, even helicopters
had to be quite close, approximately 400 to 500 feet or less, to elicit
a strong response (e.g. running) on a single low pass. Sometimes even
these distances were not sufficient as one of the examples in Appendix I
illustrates. At distances of greater than 500 feet to approximately 1/4
mile, repeated passes appeared to be necessary to elicit a strong response
even though one may assume there must have been some degree of negative
pre-conditioning during the initial capture and processing of Z.B.
Z.B.'s generally mild behavior in response to aircraft may have
been atypical, especially when considering that most observations of
bears made on surveys are those of bears fleeing from the aircraft and
often at distances considerably greater than 500 feet away. However, it
is unknown how many more bears may have escaped detection by reacting in
a possibly more normal and less violent manner than those that are seen.
During the course of this study unmarked bears often appeared, and one
could speculate that some or all of these may have been "residents"
which were finally seen rather than new immigrants to the study area,
random searching by aircraft continued throughout the study. Thus, we
do not know if the responses of Z.B. to aircraft were normal.
Hiding from aircraft was a common behavior and a significant
problem in relocating radioed grizzlies in a ten-year Canadian Wildlife
Service study of Interior grizzlies (A. Pearson, CWS, pers. comm.). One
possible example of hiding was seen with Z.B.
It seems to me that hiding may result from the cumulative effects
of aerial harassment, as in the Canadian study or in heavily hunted
populations. If Z.B. 's behavior is "normal" for the population studied,
however, hiding would not be a problem in attempting to locate bears
aerially.
In fact, the other extreme seemed to pose almost as great a problem.
That is, Z.B. usually barely moved at all even with close approaches by
aircraft. Because of his superb protective coloration Z.B. was rarely
seen by the low level aircraft that were searching for bears, even
though he was lying on open tundra in plain view more often than not.
Z.B. often merely raised his head as aircraft flew past or over, and in
only two of six flights by aircraft in which the aircraft observers were
close enough to readily detect Z.B. was he actually seen. Appendix I
contains examples of Z.B. 's typical reactions to aircraft.
Feeding and food habits
Observations of feeding activities and examination of feces and
vacated feeding spots produced a general picture of food habits between
early May and June.
Moose (Alces alces) and caribou (Rangifer tarandus) carrion appeared
to be quite important during spring and is probably more important then
than during summer. Food sources are limited when boars emerge in late
April. Snow cover then is nearly total except for windblown areas •.
Numerous bears were found on moose carcasses in late April to late May
during aerial surveys.
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In mid to late May snow began melting in patches on river bars of
major valleys, exposing overwintered Alpine bearberries0rctostaphylos
alpina) which were heavily utilized along with some roots. Dry grass
was also found in large amounts in one of the few fecal samples collected
in mid-May. Caribou were migrating through the Canning River drainage
at this time and, although Z.B. never killed an animal himself during
the time observed, he appropriated two caribou killed by the same single
wolf (Canis lupus) between May 14-20.
Both kills were made in relatively open spaces. There appeared to
be some unwillingness by Z.B. to devour them in the open, however.
Rather, Z.B. dragged the entire carcass, in one case, and parts in
another, into brush. He did eat and sleep on parts of one carcass in
the open, however. Z.B. remained attracted to the first carcass 32
hours and to the second 19 hours •
Alpine bearbearries continued to be used when available through
late May, but usage of Hedysarum sp. roots increased. This was perhaps
due to increased areas of bare ground, but also ~elting ground surfaces
made digging easier. It may be nearly impossible to extract Hedysarum
sp. roots from frozen ground in any number judging from the structure of
the roots.
Z.B. occasionally consumed newly emerged buds of Salix sp. by
clumsily balancing on his hind legs and using his paws and mouth to feed
on the ends of small twigs. Sometimes he assumed a more stable position
by sitting under a large willow bush with his back against the "trunk,"
reaching up to the overhanging umbrella of branches and draw-ing them
down with his paws. This position also permitted him the advantage of
being able to scratch his back in between bites. Willow appeared to be
a relatively unimportant source of food.
Green vegetation began appearing in early June and comprised almost
the total diet by mid-June. Equisetum sp. was heavily used and continued
to be used throughout the summer (Reynolds, pers. comm.). Green grasses
(and perhaps some sedges), apparently poorly digested, formed 100 percent
of fecal samples collected from Z.B. in mid-June at the time he was
recaptured. Reynolds (pers. comm.) said soapberries (Shepherdia canadensis)
were used very heavily in late summer.
The abundant green forage emerging in June appears to substantially
reduce the need for scavenging or predation. It is possible this could
be the primary reason sows with cubs generally emerge later than boars.
They may find it prohibitively difficult to find enough kills and/or
carrion in this period, or to compete with boars for the available food
before substantial snow melt occurs. Black bear (Ursus americanus)
studies in which it was found that black bears continued to lose weight
for two or three months after emergence lend some support to this
hypothesis (Poelker and Hartwell 1973).
Resting
Z.B. was generally not secretive in his choice of resting spots.
He seemed to prefer drier areas out of the river or creek bottom itself
5
and sometimes scraped a few pawsful of substrate away before lying down.
About half the time he could be found lying on the open tundra on the
bank just above the river, creek or gully where he foraged. He sometimes
rested in willow thickets on river bars but as much or more often he
laid down in completely open areas. The brown hair of various shades
was excellent camouflage and blended perfectly with the brown tundra of
early sunnner.
There apparently was some tendency to rest in thickets in bad
weather and more open places in good weather, but this was slight. He
also seemed to pick areas exposed to the sun or at least definitely did
not seek out shade at this time of year.
On three different occasions Z.B. climbed a little way up the lower
mountain slopes, scooped out a shallow hole in talus slopes and lay
down, and once he scooped out a hole in a snowdrift before lying down.
While on the caribou kills Z.B. either slept belly down, draped
over the carcass, or in the shallow depression formed by scooping snow
over the carcass when he was finished eating. Infrequently he rested 10
or 15 feet away for short periods.
Z.B. almost always rested directly after eating and did not engage
in long travels until rested. He appeared to be a restless sleeper,
however, and never remained in the same position for long. Periods of
very deep sleep appeared short or nonexistent. Increasing frequency of
changes of position and restlessness seemed to characterize behavior
late in the rest period.
Traveling
Traveling was defined in a strict sense of movement only, with no
associated feeding. Most often Z.B. walked and fed, stopping here and
there, or intensively used one area with very little movement as in
digging roots or feeding on carrion. The distinction of a separate
"traveling" class of behavior appeared to be real, however. Z.B.
sometimes simply began moving with no apparent interest in feeding or
any other activity.
Excluding several short travels to and away from carrion while Z.B.
remained on or near them, traveling generally appeared to occur after
feeding, and from very scanty data, seemed generally to be followed by a
rest period. His travels often lasted for several hours, and obstacles
such as deep, rotten snow, thin ice and open creeks did not slow him,
much less divert or stop his march. Measured rate of travel was about
3-4 m.p.h. Traveling seemed to occur most frequently during the twilight
hours between 9 p.m. and 4 a.m.
Breeding Behavior
One detailed observation of breeding behavior was recorded on June
17-18. After approximately two hours of searching for Z.B. with a
helicopter on June 16, Z.B. was sighted in a broad, low tributary valley
of the Canning River in the company of a 4.5-year-old collared female.
6
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The female, W.B., ran off, crossed the South Fork of the Canning
River and ran up the other side while we tranquilized Z.B. and fitted a
new radio. The helicopter departed and we began our observation again
at 0400 on June 17.
At 1035 we saw the female alternately running and walking upstream
in the area of Z.B.'s tagging. She continued gradually upstream,
stopping frequently to raise her head and smell the wind. Z.B. was
slightly downstream of her and sleeping, not yet completely free of the
effects of the drug although he had been up and moving some. At 1053
the female stood oriented downstream for one full minute, then lay down
in the sun next to the creek among very sparse willows. She continued
to raise her head and smell the wind frequently, perhaps for our lingering
scent from the tagging spot, or for Z.B.
At 1457 a large, dark 19.5-year-old boar named S.B. appeared at the
tagging area next to the creek, smelled the trampled ground, then rubbed
his neck and collar on the tundra for 10 seconds. He then headed diagonally
upstream toward the creek, apparently following the female's trail.
S.B. reached the creek, crossed to the middle, lay down in the water for
30 seconds (it was a warm, sunny day), then headed upstream to where the
female had been lying. Meanwhile, she had moved further upstream. S.B.
was evidently following her scent and traveled upstream at a fast walk,
stopping only infrequently to look about. At 1541 S.B. was a mile
upstream of where he was first observed, and the female was only a
hundred yards ahead, then she started to run upstream ahead of S.B. In
general, there ensued a walking "chase" in which the female kept 3 to 15
yards ahead of S.B., sometimes stopping to wait for him to catch up, and
sometimes turning to face him until he came near. The detailed description
of this behavior is provided in Appendix II. This interaction, beginning
at 1541, did not end until 38 minutes later at the end of the 17-minute
copulation period. A limited amount of "display" occurred after this,
but mostly the two bears fed and rested together for the next 6-3/4
hours (until 2305) when they began a slow upstream movement while feeding,
led by S.B.
At 2350 the female left S.B., crossed the creek and began digging
on a hillside. She soon discovered S.B. was 1/2 mile upstream from her
and still moving whereupon she began rapidly walking in that direction,
apparently following by smell the same path taken by S.B. S.B. disappeared
over the top of the pass at the head of the valley at 0030 June 18 with
the female five minutes behind and alternately running and walking to
catch up. The location and direction of movement are shown in Fig. 1.
Z.B., considerably downstream of the preceding action, slept through
most of it, probably still slightly under the influence of the drug.
This observation occurred 4 miles from the 4.5-year-old female's place
of capture 16 days earlier, 6 miles from the 14.5-year-old Z.B. 's place
of capture 38 days earlier and 38 miles from 19.5-year-old S.B. 's place
of capture 37 days earlier.
Interactions with other animals
Z.B. had the opportunity to interact with caribou, moose, ravens
(Corvus corax), a wolf, an eagle and other bears. All of the close
7
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Home range of grizzly bear "Z.B.", May 14-June 17, 1973.
S.B., W.B. and B.B. other grizzlies found in the area.
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interspecific interactions we observed centered around the two caribou
kills, however.
Although other grizzlies in the study were commonly found on moose
carcasses early in the spring, Z.B. appeared to peacefully co-exist with
the 8-12 moose inhabiting the high willows of the 10-mile length of the
upper Canning which was his most frequented section of range: Several
times we saw Z.B. enter dense, isolated willow bars which also contained
one to three moose, including cows and calves, and a short while later
exit the other end of the bar. Sometimes we could see that the moose
appeared aware of Z.B. 's presence and would slowly move through the
willows themselves, but there were never any violent reactions or attempts
to escape such close proximity to the bear.
Small bands of caribou migrated down the Canning River in late May
and moved past Z.B., from 25-200 yards away. Z.B. never seemed to be in
sight of the caribou, however, and was either resting at these times or
feeding in the willows. He may have been aware of their presence,
though, through smell.
On only one occasion did any interaction occur and that was inadvertent.
After feeding on a caribou carcass, Z.B. trudged up the mountainside to
a large snowbank at the foot of a talus slope, scooped out a hole and
flopped into it in the hot, early afternoon. Two small groups of caribou
passed down the valley while he slept. At 1900 hours, 19 caribou were
200 yards away and feeding slowly toward where Z.B. lay. One hundred
yards away they encountered his fresh trail and showed no reaction at
all. At 50 yards, one caribou lay down while the others fed even closer.
Z.B., always a somewhat restless sleeper, was sprawled on his back
in the hole, quite invisible to the caribou and apparently unaware of
them also. He stretched his hind legs in the air once which the caribou
apparently did not notice, then he suddenly rolled over, waving all four
feet in the air. The caribou closest (less than 50 yards) ran down the
hill instantly, though Z.B. resumed sleeping, still not aware anything
was ~round. The caribou did not run far but then continued down the
hill, turned upstream and angled up the mountainside single file, and
continued to criss-cross up and down the valley for the next 30 minutes,
stopping once at one of Z.B.'s trails to smell, continuing on, then
reversing direction again. Z.B. continued to sleep through this period.
Ravens seemed to be a considerable problem for Z.B. He zealously
guarded his appropriated kills from the smallest infringement by ravens
and in turn the ravens harassed him almost unmercifully. Z.B. often had
to sleep on top of the kills to protect them from ravens, and even then
they would attempt to sneak up behind him to grab a bite. Although the
ravens were amazingly sly, we never once saw one get a single bite of
caribou when Z.B. was on the kills. At the last moment, whether Z.B.
was attempting to sleep, or awake and feeding, and regardless of the
number of birds (up to 10) he had to watch, Z.B. would swing his head
around in time or swat at them with a paw. However, Z.B. never struck
one of them, though the raucous cries of fighting and escaping birds
resounded across the valley for hours. In the end, the ravens would
give up tormenting Z.B. and he would finally be able to rest.
9
We discovered the first caribou kill when we spotted a single grey
wolf feeding on the carcass of a pregnant female two miles downstream of
our position at 1420 on May 17. The wolf fed briefly then departed
downstream. A golden eagle (Aquila chrysaetos) which had been sitting
on the snow 200 yards away then came in to the kill and began feeding.
When Z.B. arrived at the kill almost two hours later, the eagle reluctantly
gave way to him and was never seen again on the kill, even when Z.B. was
away from it. The wolf was not seen to return either while Z.B. was on
the kill, although he inspected the kill site at night on May 19 after
Z • B • had left.
At 0040 May 19, Z.B. finished with the carcass and walked away,
obviously smelling the air, and even rose up on his hind legs once to
smell. Walking slowly downstream he came upon a very fresh yearling
caribou carcass less than 1/2 mile from the first carcass. Picking up a
big piece of rib cage and front legs in his mouth he carried it off the
gravel bar, across the creek and upstream 50 yards where he lay down
with it in the willows and began eating.
At 0400 Z.B. was sleeping next to the major portion of the carcass
he had dragged off into the bushes when a single grey wolf appeared 15
feet away. Z.B. sat up and faced him as the wolf circled half way
around the bear and carcass then walked away, crossed the creek and fed
on the sparse remains of the carcass remaining at the original kill
site. Z.B. lay back down close to the carcass. The wolf fed only a few
minutes, then departed downstream. Probably there was almost nothing
left to feed upon. We suspected this was the same single grey wolf seen
on the first carcass and was probably the predator which killed them.
At 1732 the same day, we spotted a single grey wolf 1-1/2 miles
away, moving rapidly upstream. At 1750 the wolf arrived at the major
part of the carcass again and Z.B. was again resting beside it. Upon
the wolf's arrival, Z.B. immediately stood up on all four feet facing
the wolf. In only a few seconds, the wolf trotted away. Z.B. remained
standing two minutes then curled up next to the carcass again.
In another minute though, Z.B. was up again, walked to the edge of
the creek, sniffing and looking in the direction the wolf had gone,
crossed the creek to the kill site, sniffed around looking in the direction
the wolf had gone, then walked 15 feet in that direction. Then he
stopped, returned to the kill site, pawed through the remains for 20
seconds and returned to the piece of carcass in the bushes.
Z.B. sat down and began eating on the carcass for the next 25
minutes, then lay down and slept for 20 minutes before arising, returning
to the kill site to poke around a few minutes and permanently abandoning
the second caribou kill.
Meanwhile, the wolf arrived 1/2 mile upstream at the first caribou
carcass, sniffed around for a minute, then walked off 50 yards and lay
down on the snow. Two hours after Z.B. permanently left the second
kill, the wolf returned to the site, found the bear gone and lay down
and began chewing on the remains at 2100 hours. We never again saw the
wolf or again saw Z.B. eating carrion. It appeared that bear-wolf
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encounters were common to these two individuals and no time was wasted
in sparring or contesting the carcass. The meetings lasted only a few
seconds and neither animal appeared excited or alarmed.
The only contact with another grizzly, besides the breeding observations
described elsewhere, occurred on May 25 when we discovered a blond bear,
probably a female, 1/2 mile from our camp. Her location is shown as
"B.B." on Figs. 1 and 3. Detailed observations could not be made because
we had to vacate our camp just before the bears met. Z.B. was on a
collison course with our location and we had to climb higher on the
mountain. We did watch the blond bear, standing 30 yards uphill from
the tracks Z.B. made as he passed her, and for the next 20 minutes she
continually sniffed the air every few feet as she very slowly traveled
in the direction of the tracks. The two bears may have had a short
encounter in the stream bed below us, but Z.B. was soon seen two miles
upstream, feeding on overwintered berries while we continued to watch
the blond bear digging roots. I suspect no more contact occurred than
close range sighting and smelling of each other, which was interesting
in view of the probable sex of the bear and the date of meeting in
relation to the breeding season.
Movements
Z.B. 's movements appeared to be controlled almost exclusively by
food availability. During May, Z.B. was found solely on the river bars
of the main Canning River. Rarely did we see him on the banks more than
50 feet above the river during this early period. Not surprisingly,
snow first melted off the floor of the main river valley, uncovering
overwintered Arctostaphylos alpina berries and providing patches of bare
earth that were dug up for roots. Not until green grasses appeared in
mid-June did Z.B. occupy side tributaries or did his movements begin to
broaden away from the main Canning River valley.
Z.B. 's home range, determined from all known positions between
tagging on May 10 until ground tracking ceased on June 18, was a 27 mile
length of the Canning River from its headwaters nearly to the Marsh Fork
junction plus a four mile section of a major tributary of the Canning
(Fig. 1). By June 17, the broad, low valley indicated was snow free
and lush with grass along its creek. This movement to higher elevations
and a side tributary coincided with a general "disappearance" of bears
in the main valleys as reported by the rest of the study team who were
still attempting to locate and tag bears.
Daily movements varied from zero, when Z.B. was on a kill, to 16
miles during a 10-hour period (Figs. 2 and 3). Daily movements averaged
about six to eight miles per day, however, when Z.B. was not on a kill.
In general, Z.B. repeatedly traveled up and down a limited section of
the Canning during our observation period.
Activity Patterns
Despite the limited number of days of observation, some patterns of
activity did emerge among the three general types of behavior --feeding,
resting or traveling. For all days of 24 hour observations combined,
Z.B. spent 31 percent of his time feeding, 59 percent resting and 10
percent traveling.
11
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Observed Movement
Inferred Movement
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13
When individual days were divided into six hour segments, however,
it was obvious that the different activities were not uniformly distributed
throughout the day. Table 1 shows the percent of Z.B.'s time devoted to
each activity during different quarters of the day. The 24-hour day was
divided into quarters at those points which appeared to maximize variation
b.etween quarters.
Table 1. Percent activity by six hour periods for all observations combined.
Activity
Feeding
Resting
Traveling
Morning
0330-0930
42
54
4
Time
Midday
093Q-1530
40
57
3
Evening Night
1530-2130 2130-0330
29 16
60 64
11 20
"T" tests were used to determine if differences existed in the mean
time spent for any given activity among the different quarters of the
day. Table 2 gives the means and Table 3 shows the results of the "t"
tests which were significantly different at 95 percent and 99 percent
levels of confidence.
Table 2. Mean number of houri spent feeding, resting, or traveling per
quarter of the day.
Feeding Resting Traveling
Morning (0330-0930) 3.3 3.7 .2
Midday (0930-1530) 2.7 4.0 .2
.Evening (1530-2130) 2.3 4.8 1.0
Night (2130-0330) 1.5 5.3 1.3
1 Total hours per quarter do not equal 6 hours because of sampling
method error.
Table 3. "T"-test results for differences in mean time spent for a given
activity versus quarter of the day. X = Significant difference.
Feeding
morning vs. evening
morning vs. night
Resting
morning vs. evening
morning vs. night
midday vs. night
Level of Significance
95% 99%
X
X
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Table 3. Cont.
Traveling
morning vs. night
midday vs. night
X
X
From these tables, one can determine that Z.B. fed more in the
morning than either evening or night. Conversely, he rested more in the
evening or nlght than in the morning (and also rested more at night than
in the midday), and that he traveled more at night than either morning
or midday.
When the-24 hour day was divided in half, at the points which
maximized the variation in time spent feeding, the day was divided at
0330 and 1530 into the two parts. Maximizing the variation for time
spent resting produced a day divided at exactly the same points as
feeding. Interestingly, the traveling activity pattern produced the
same results, and if the 24-hour day was divided into a 0330 to 1530
"morning-midday" period and a 1530 to 0330 "evening-night" period,
variation in time spent for each of the three activities was maximized.
Feeding was the predominant activity for morning-midday and resting and
traveling for evening-night. These differences were all significant at
the 99 percent level (Table 4).
Table 4. Mean num~er of hours spent feeding, resting, or traveling per
1/2 day.-
morning-midday
(0330 to 1530)
evening-night (1530 to 0330)
Feeding
3.0
Resting
3.8
Traveling
0.2
1.9 5.1
1 Total hours per half day do not equal 12 hours because of sampling
method error.
1.2
Since an average of only 15 percent of Z.B.'s time during evening-
night was spent traveling, I do not believe this accounts for the popular
notion that bears are more easily observed from the air at night than in
the day. From our observations Z.B. should have been approximately as
visible during feeding as during traveling. There must be other factors
operating, or the limited amount of data on this one bear do not reflect
the usual patterns. Activity patterns could also change through summer
and fall. Especially, there were indications that the high temperatures
of summer midday might reduce activity. We observed two instances in
which bears laid down in a water pool or stream on hot middays for a few
seconds, apparently to cool off. I believe early June was too early to
notice a regular midday reduction of activity due to heat. Temperatures
were beginning to get hot, however, especially in direct sunlight where
temperatures greater than 90-100°F could be experienced. Snow and rain
appeared to not affect normal activity patterns, but data were limited.
15
General Comments
Visual ground tracking of grizzly bears in the Arctic is difficult,
though definitely feasible. We found that a two-man team was necessary
to provide 24-hour monitoring. Radio collaring assistance was still
necessary, however, because visual contact was too frequently lost
during snowstorms, rain, ground fog and when Z.B. occasionally entered
large areas of dense willows. Loss of contact in willows was generally
not a problem in the spring, however, because patches tended to be small
and we could see into them from our elevated camp sites. Leafing out of
the willows in summer would definitely reduce visibility and could
reduce the amount and completeness of data collected, depending on the
bears' habits at that time. As already indicated, the trend of dispersal
from the valley floors of major drainages in early summer to higher
elevations in side tributaries where fewer willows exist, may mitigate
the adverse effects of leafing vegetation. High water and rotten snow
during spring breakup were other serious problems affecting our ability
to maintain visual contact with Z.B.
By essentially living half way up the mountain sides while Z.B.
occupied the valley floor, we were very successful in preventing our
presence from affecting Z.B. 's movements and behavior.
One of the shortcomings of the 32mHz frequency radio collar used on
Z.B. was that the frequency seemed susceptible to being reflected by the
terrain features. Tests conducted from time to time while in visual
contact with Z.B. showed that the bearing obtained did not always point
directly to Z.B. No common source of this error was obvious. This
shortcoming was the factor directly responsible for the one time Z.B.
became aware of our presence and fled. Since we could not pinpoint his
location on that occasion we had to utilize a helicopter to relocate
him. The helicopter dropped us too close to Z.B. and he smelled us.
This radio contact was also "line-of-sight" with its inherent
limitations. If Z.B. rested his head between two tussocks on the bare
tundra, the signal could be nulled. The radio generally fulfilled its
purpose, however, of allowing us to relocate Z.B. after loss of visual
contact, though its undesirable characteristics prevented us from making
accurate plots of movements during snowstorms and heavy ground fog.
The radio failed after a few weeks because of its lightness of
construction. It had not been designed for use on bears. Also, a web
collar, rather than the more rigid vinyl tugging used may have been less
irritating to the bear.
In summary, visual ground tracking of a grizzly bear on a 24 hour
basis was a demanding, sometimes monotonous, and often difficult task.
It is a feasible and highly effective technique, however, for gathering
life history information. There is no other way to acquire the detailed
information afforded by this approach.
16
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ACKNOWLEDGMENTS
My sincere thanks to Mark Lenarz who began this project with me;
Roland Quimby, Harry Reynolds and John Klingel for their personal concern
and support; and Pat Reynolds for sharing the arduous task of many long
hours of watching.
LITERATURE CITED
Poelker, R., and H. Hartwell. 1973. Black bear of Washington.
Washington State Game Department Biol. Bull., No. 14. 180pp.
PREPARED BY:
Spencer Linderman
Game Biologist
SUBMITTED BY:
Richard Bishop
Regional Research Coordinator
APPROVED BY:
Research Chief, Division of Game
17
Appendix I. Reactions to Aircraft.
May 14 at 1609 hours Z.B. was resting on the lower slopes of the
mountains at one side of the main river valley. Sixty-five seconds
after first hearing a Cessna 185 at 500 feet AGL, and when the aircraft
was still one mile down river from the bear, Z.B. raised his head to
stare out across the river and watch the plane pass by approximately 3/4
mile away. As soon as the plane was out of sight of the bear, Z.B. put
his head down and resumed his resting position. The C-185 could be
heard by us for more than three minutes total time. The aircraft continued
up the valley then returned a few minutes later at 1000 feet AGL, flying
parallel to the river on the same side as Z.B. and about 1/3 mile away.
When the aircraft was 1/2 mile away, but just before coming into sight
of the bear, Z.B. raised the front half of his body off the ground and
remained in that position as the C-185 passed and until the plane was
three miles away and well out of sight.
On May 18 at 1613 hours, Z.B. was resting after a big meal, in a
scooped out snow drift at the base of the mountains along the river. An
FHllOO helicopter at 500 feet AGL approached flying up the center of the
river valley approximately 3/4 mile from Z.B., then turned to the opposite
side of the valley and landed at our camp, one mile from Z.B. The
helicopter could be heard by us for three minutes before arrival.
During the whole episode of landing, shutting down, warming up and
departing Z.B. raised his head only once to look about.
A bit later, at midnight, Z.B. was standing over a caribou kill
eating, when a fixed wing aircraft passed high overhead, but with a
distinctly audible sound. Z.B. gave no indication of its presence.
On May 19 at 0923 hours, just after Z.B. finished eating and lay
down on top of a caribou carcass, we heard the distant hum of an aircraft
for 30 seconds. Z.B. raised his head and looked upstream in the direction
of the sound.
On May 24 at 2305 hours, Z.B. was lying on open tundra at the brink
of the river bank when a C-185 came down the valley at 400 feet AGL on
the opposite side of the river from him (1/2 mile away). He passed
downstream, then returned via the same route. Z.B. then sat up and when
the aircraft made a third pass, but this time at 200 feet AGL and (unwittingly)
nearly directly over Z.B., he ran down the bank into heavy willows on
the gravel bars.
An observation on May 20 at 1009 hours may illustrate several of
the generalizations about Z.B. 's behavior. Z.B. had been up from a nap
for a half hour, defecated and was traveling steadily upstream, poking
about, scratching himself on willows but not yet feeding. He was on the
open gravel river bars, crossing one channel when he heard a helicopter
coming downstream. Z.B. stopped and looked in the direction of the
sound a few moments, looked behind him to the left and right, then
continued walking upstream on the open bars. The helicopter passed
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directly over him at 400 feet AGL and turned and went back upstream, but
several hundred yards away along the side of the valley. The helicopter
then made a second low pass downstream and this time Z.B. took off,
charged across the river, climbed the river bank at a run, stopped once,
then walked rapidly downstream. The helicopter was approaching on
another 'close pass when Z.B. began running again, stopped and turned
toward the sound, then resumed running and continued to run at least a
quarter mile until out of sight downstream.
Appendix II. Breeding behavior (based on field notes).
June 17
1541 hours: Spotted W.B. 100 yards ahead, started to run upstream, she
stopped, looked back, running again, stopped, looked back, he is running
toward her, still about 100 yards away, she ran up hill, stopped, he is
walking forward, he turned and walked away from her, she is standing
uphill from him, looking toward him (75 yards away), she took a few
steps toward him, he is walking upstream, not directly toward her (cannot
see her), she takes few more steps toward him, 50 yards apart, he seems
to be following her trail, she walks toward him 30 yards apart, walking
toward each other, just 10 yards apart, she did not go straight toward
him but turned and went upstream, he followed after her 10-15 yards
apart, both heading upstream, S.B. holds head down while walking, W.B.
holds head more horizontal, bears are about 6-7 yards apart, now traveling
upstream and slightly away from creek, both stopped, W.B. looking back
at S.B., he moves on, she moves on, moving downstream, zig-zagging their
way up the hill, he stops, she stops, looks back, both moving uphill,
about five paces apart at times (3 yards), W.B. in the lead, S.B. behind,
both are moving at a brisk walk, S.B. caught up to her, she turned
sideways, he put his head up to her neck for a few seconds, then continued
walking, S.B. two yards behind, she ran ahead, then stopped and turned,
again he approached face to neck, then they continued walking, bears
have left creek and have been traveling north across valley, almost to
north side, bears traveling almost nose to tail, she stopped turned,
confronted him face to face for a few seconds then continued on, stopped,
did same thing, stopped, confrontation is longer each time, facing him
than backing up a few steps, she turns and they continue on up the hill,
she stopped, he pulls up beside her, then off again, W.B. still in lead,
she stopped, he attempted to mount, put paw over her back, he is mounting
her, parted for 50 seconds, mounted her again for about 4 or 5 seconds,
both bears disappeared behind ridge, reappeared, S.B. attempted to mount
her again but was unsuccessful, bears are out of sight again, bears move
forward, stop, mounting takes place and then they move forward, mounted
her again, she turns a few steps while he is on her (i.e. turns half way
around) every now and again, then stands perfectly still, 4-1/2 minutes
have passed, he is still on her, she takes few more steps (after being
still for approximately a minute and a half) and turns in half circle,
two separate movements by female, taking a few steps and/or turning in a
half circle have occurred in sequence or separately several times during
mounting which now has been in progress for nine minutes.
1618: She began throwing head side to side, attempted to grab his leg,
threw herself down on side.
1619: Parted, stood side by side, lasted 17 minutes.
1620: Began walking few steps with her in lead again, he is approximately
3-5 yards behind, he goes downhill, she stopped, looking, then follows
him 10 yards, he comes back uphill and disappeared, she stopped.
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1623: Cat and mouse play, male out of sight, female standing on ridge
looking across little gully to where he disappeared, looking towards
him, then away, shook, still looking towards him.
1625: Female sat down, facing direction he has gone.
1626: Male reappeared, crossed gully toward female who has started
walking up the mountain a few steps, bears about 10 yards apart, male
moves closer to about 15 feet, both are walking up hillside, heads are
down (eating?) as they stop for a few seconds, then continue walking and
stopping to eat.
1630: Still walking and eating together.
1634: Male flopped down on ground, female continues to feed.
1640: Male up and both feed.
1644: Both lying down five yards apart, and apparently asleep.
1655: W.B. changed position and five yards on other side of S.B., no
sign of Z.B.
1658: W.B. up and started downhill, S.B. following after W.B. 50 yards
down, she stopped and waited for him then traveling down together, W.B.
leading.
1700: Stopped, standing laterally apart 20 yards.
1701: S.B. crashes on side, W.B. stands then crashes on stomach at
1703, 3-4 yards apart.
1735: Both bears sleeping.
1737: Both bears walking, walked a few hundred yards then began feeding.
1740: S.B. male crashes again, W.B. female still feeding, she gets
about 100 yards away, S.B. male lifts his head, watching her leave,
finally scrambles to his feet and follows after her, she lies down, he
lies down within 10 feet of her, (S.B. male walks with a very strange
gait, swings his hind feet forward with a wide rolling movement as
though his hips were very stiff).
1745: S.B. male still lying down, W.B. female up and walking (S.W.
across valley), she gets about 150 yards away, he lifts his head, looks
around, staggers to his feet, shakes his body, and takes out after her.
1750: They are both still traveling, not stopping to eat.
1752: They stop, facing each others heads, he turns and approaches her
rear, she moves away, bears are face to face again, and once again he
approaches her rear, face to face once more, heads very close together,
then she hits him in the face with her left front paw (playfully?), then
backs up several steps as he approaches her.
1755: Both bears lie down, very close together, almost appear to be
touching.
1756: Both bears are up, S.B. male standing still, W.B. female walking
away.
1758: W.B. female is 100 yards away from S.B. male still walking fast,
he hasn't moved.
1759: S.B. male gets to his feet and takes after her once again.
1800: S.B. male catches up to her, she is feeding (head down), he
approaches her rear, she turns around quickly to face him, resumes
feeding and S.B. male immediately crashes once again.
1801: W.B. female is off traveling once again, S.B. male is still lying
down, she stops to feed approximately 100 yards away from him.
1805: W.B. female has disappeared from view into a little gully. S.B.
male lifts his head, is on his feet again after her, they both reappear
on far side of gully and began feeding, they are partly hidden from view
by contours of land and vegetation.
1810: S.B. male appears to be lying down once again and W.B. female is
walking around.
1814: Both bears are up feeding, within a few feet of each other.
1816: W.B. female disappears into gully, S.B. male follows her.
1820: S.B. male reappears, standing up, then crashes, out of sight,
W.B. female walking away, about 150 yards from where S.B. male was last
seen.
1824: W.B. female stops, lifts head, smelling, then sits down for
approximately 30 seconds, then she is up again walking, stops again
sniffing east, no sign of S.B. male.
1830: She is still walking fairly fast, has reached the main creek
flowing through the valley and is traveling downstream.
1831: She is feeding on vegetation, still no sign of S.B. male, he must
be napping.
1833: She stops, turns around, stands up looking direction from which
she had come, walks a few steps forward, stops and stands up again,
looking back, continues walking downstream.
1836: She stops and looks back once again, then begins feeding on
vegetation, walks a few steps then stops to "graze."
1850: W.B. female still feeding in same area.
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1855: W.B. female still feeding in same area, no sign of S.B. male.
1859: W.B. female feeding, stops occasionally to look back upstream,
here comes S.B. male walking right toward her, W.B. female lies down,
head oriented in the direction of S.B. male, who begins feeding on
vegetation.
1902: W.B. female gets up, begins feeding also, two bears are about 10
yards apart.
1905: Two bears are still feeding about 15 feet apart, W.B. female is
lying down while eating.
1906: W.B. female begins walking, followed very closely by S.B. male,
he appears to be sniffing at her rear, she turns several times to look
back at him, she finally sits down on hind feet, he walks around sniffing(?)
her, they lick or bite at each others heads, for a few seconds they
appear to wrestle with mouths and heads, then she backs up and breaks
away, she sits down again and he walks around her sniffing, she lies
down, he walks around her once more and lies down next to her.
1925: Two bears are sleeping in same location.
1931: Two bears are sleeping in same location.
1944: Two bears are sleeping in same location.
2000: Two bears are feeding in same general vicinity.
2012: Two bears are feeding in same area.
2017: Two bears are feeding in same area.
2030: Bears are lying down (sleeping?) in the same area where they have
been feeding.
2046: Both bears are feeding in same area as they have been for the
last hour or more.
2050: Z.B. (!) spotted on top of the bank where he was last seen this
morning (must have been sleeping behind that bank all day), he was
standing up when first seen, now is lying down (2057).
2100: S.B. male and W.B. female are still feeding in same general area,
they are about 150 yards apart, Z.B. is still lying down.
2104: S.B. male who wandered upstream has returned downstream to W.B.,
he approaches her, she turns sideways, then turns to face him, they held
their heads together several se.conds but could not see what they are
doing, S.B. turned and walked away, both resumed feeding, Z.B. is still
lying in same position and location.
2108: Z.B. lifted his legs in the air, rolled over and lifted his head,
but lay back down in same position.
2118: Z.B. still lying down, but has changed positions, his head is now
uphill, cannot see S.B. or W.B. (in a gully or the willows?).
2125: Z.B. in same location and position, still cannot see S.B. or W.B.
2130: Z.B. still lying down.
2145: Z.B. still lying down.
2210: Supercub approaches from south, upwind, and Z.B. appeared to
raise head or whole front half when plane very near (sound was carried
away from bear on plane's approach), 1/4 to 1/2 mile away, plane circled
over on sheep survey 2,000 feet above ground level and headed back
south, Z.B. lay down in 20 seconds, wind northeast 10-20 ~.
2212-2217: Z.B. up, changed position, over a bit and down on same
gravel bar.
2223: W.B., S.B. spotted lying almost touching at edge of stream on
green bank, 30 yards upstream from junction of Rolling Bear Creek (RBC)
and the small tributary entering upstream from north, Prairie Hill Gulch
(PHG).
2235: All hands same.
2242: W.B., S.B. walked over edge to stream, out of sight.
2255: S.B. feeding on green bar between two streams.
2300: W.B. feeding also, 2Q-30 yards apart, Z.B. lying down.
2305: W.B., S.B. fed close together then began slow movement upstream,
S.B. leading.