Warmer temperatures are melting low and mid-mountain snowpack, exposing berry shrubs for spring development — and that is good news. The previous two years saw poor berry crops back-to-back, which resulted in over 50 bears from Whistler's meta-population being lost mostly due to conflicts with people/garbage and being struck by vehicles along Highway 99.
Poor berry crops also lowered cub birthrates and survival of sub-adult bears (less than four years old). In 2011, only seven cubs were counted in spring and by fall five had survived. One cub was lost from a three-cub litter belonging to Amy, a brown mother active through the Spruce Grove-Lost Lake-Chateau Golf Course corridor up to Blackcomb. Another cub was lost from a two-cub litter belonging to Jeanie last spring and subsequently, after Jeanie was destroyed last October, the surviving cub was submitted to a wildlife shelter.
These low cub years also yield fewer "teenage" yearling bears in the years following. Low cub years also force unproductive females into the same reproductive cycle the following year.
When all females get pregnant in the same year, they are in reproductive synchrony. In 2011, 16 out of 17 females in the ski area sub-population bred last spring and are due to emerge with cubs this May. You wouldn't expect them all to have cubs this year due to the poor berry crop last fall, but the older females should have cubs because as the population has experienced high mortality, competition goes down among surviving bears, allowing the remaining bears to make better use of the lower supply of berries.
And of those 16 females, six have never been seen with cubs, including some daughters growing up in the resident population.
The population should remain stable with gradual increases during good berry years. Even then, I don't think we will experience high cub years because younger mother bears usually produce fewer cubs. That said, in 2007, Elly and Brownie, two 10-year old females, produced three-cub litters while older females produced one to two cub litters.
So Whistler bears are getting old... we all age, and bears are no exception.
The last couple of years a shift has begun in the age structure of the population where resident mother bears first identified from the mid-1990s, when I started researching, are disappearing from the population. A bear's body is usually not discovered, but it is realistic to assume these females are dead because established females usually do not simply leave their area. However, it has been documented in other bear studies that resident mothers leave their annual range to allow daughters use of the original range. I have not observed this behavior in Whistler. And because, historically, Whistler has had such a dense population of bears competition is high, so it would really be tough on an established female to try to live in an unknown area.
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