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Bear Update

Bear Researcher The large female black bear drops heavily onto her front left leg, the paw skidding along a slick, rain-soaked log.

Bear Researcher

The large female black bear drops heavily onto her front left leg, the paw skidding along a slick, rain-soaked log. A sharp pain stabs her left shoulder but she shakes it off and slumps into a dense clump of berries between two old growth cedar stumps. Her large triangular-shaped head dives into the canopy of elliptical foliage. Colour perception is high and she immediately targets blue and shiny purplish-black berries. She nibbles the berries quickly, detaching them from their single stems. Her 18-year old eyes work ahead of her mouth, almost bird-dogging the next location of disaccharide sugars. The accumulations of these 8-mm diametre juicy fruits are the foundation to successful hibernation and gestation.

Vaccinium (huckleberry and blueberry) are now at their peak above mid-mountain elevations (>1,400-metres) surrounding Whistler. Early September’s sunny, dry days saved approximately 60 per cent of the otherwise, 2-4 week late summer-fall berry crop. Up to 20 per cent of the crop has succumbed to mould, rot, and shrinking — a sign of too much rain during the summer (July-August) swell stage of the berry.

The female straddles over the next clump of 130-cm tall shrubs. Like a fork, the angled prongs of berry stems stick up around her 94-cm shoulder height. Her head methodically surveys the angled micro-forest. Within seconds eight berries are nibbled away using loose, flappy lips. She orients right, slurping 11 more berries then backward around the patch consuming six more.

Berries are swallowed whole — chewing only wastes time.

She pivots to the left and takes in 16 more berries. Her pivot reveals a limp which only slows her momentarily — a knee-jerk reaction from an old fracture, healed during hibernation four winters ago. Berry consumption for this female is rewarded on a small scale, but only she knows the persistence needed to accumulate time and gross volume of berry intake.

Her fight is with her body’s biological clock. Four weeks ago, in mid-August, 1-3 eggs (usually) stalled at the blastocyst stage following fertilization and refused to implant until late November and the outcome of her pre-denning weight. Now Marisa, the oldest resident mother on Blackcomb Mountain, maximizes daily foraging effort all daylight hours to gain as much weight as possible before the onset of snowfall at higher elevations, signaling the end of the berry crop.

In early December, X number of eggs will implant, depending on her weight gain, and cubs will be born from mid-January to mid-February after only 40-60 days of fetal development. If females do not gain sufficient weight, few to no cubs are born.

The correlations between climate, pollination, berry phenology, and bear foraging strategies is the most powerful variable in regulating cub production and survival (of young and old) in the bear population.

Two kilometres away, sharing the same fall foraging area as Marisa , a younger mother ploughs energetically through a thicket of berries. She consumes 86 berries in two minutes — and keeps on going.

Three younger bears fan out around her side foraging with equal intensity but less accuracy. These 70-lb offspring, far too large in stature for first year cubs, were born in January 2006 and remained with their mother through her second spring when normally she would have pushed them away at 18-months (in June 2007). Following family break-up, resident mom Zoe , would have then bred to produce cubs in January 2008. Instead, for some reason, Zoe kept her family intact, did not mate, and now pushed her otherwise two-year breeding cycle to three years, potentially producing cubs in January 2009 instead of 2008.

Some six kilometres south of Blackcomb’s north-slope, across Fitzsimmons Valley, a larger mother ascends the dense berry-producing field of the Green Acres ski slope. An old tattered radio collar is disappearing beneath the skin folds of accumulating fat. With the agility of a deer, she hops up two metres from log to log and settles into an erratic body motion to consume a patch of oval-leafed blueberries.

Down-slope, shrubs rustle in two separate locations as stocky, healthy yearlings poke their head up through an ocean of berries, taking a few seconds out from frenzied berry feeding to ensure their mother’s whereabouts.

Sixty metres away a fourth rustling catches the mother’s attention and she rears to scent a tagged 300-lb male (with a black face) silently foraging with no concern for the family. Katie, the large mother resident to Whistler Mountain’s north-side, drops and huffs. The yearlings immediately rear thrusting their noses and gulping air to “see” the strange male. Katie sways her head and resumes foraging. The yearlings follow her lead. Berries override concerns of proximity and toleration is high amongst bears during fall weight gain.

Katie added an interesting flare to Zoe’s situation of not mating and keeping her three yearlings, in that Katie pushed her yearlings away in early July then mated (as usual) but then, by late July, her two yearlings were seen in association with her one at a time to eventually form a “re-grouped” family in early August. The family has remained since and Katie, I assume, is pregnant as she was observed mating with two different males in July. This is the first time in 22 years that I have observed this situation. Katie was the first mother, in 1997, to keep offspring for 2.5 years.

This year I sense a higher than normal amount of stress in the female population of black bears at Whistler. After following the seasonal behavior of 60 female bears (all ages) for up to 14 years I am seeing females breaking from annual trends and exhibiting new strategies to overcome human and natural-caused negative influences.

This fall it will be interesting to see the condition of many bears as a result of a late and reduced berry crop, an increase in human disturbance, high garbage availability (as usual), and unique situations of reproductive biology. The mountain ash crop looks above average — in abundance at higher elevations — and is the next berry to ripen for mid-late September to late-October foraging.