Bears competitive in hunt for berries 

Aggressive males may make life difficult for mothers, cubs


A brown young-adult female black bear uses her forepaw to steady a huckleberry stem while slurping succulent berries through loose, floppy lips. The critical high elevation (1,500-1,700 metres) Vaccinium (huckleberry and blueberry) crop is now peaking as of Sept. 14. Berries are scattered but overall consistently available across most mountain slopes.

Bears are working more to consume berries: more moving than consuming but established resident adult bears, including most cubs and sub-adult bears, are gaining weight.

The Sorbus crop (Sitka mountain ash), large clusters of bright orange/red berries, are following Vaccinium in ripening. These three berry species are the most abundant and productive berries for bears in Whistler.

There is, however, an increase in competition amongst bears throughout berry patches. I am seeing a 40 per cent increase in male aggression toward mothers and younger males.

On the north slope of Whistler Mountain, where commercial bear viewing can monitor six to nine hours each day of bear sightings, large adult males dominate the Greenacres berry shrubfield. This 900-metre long family ski zone (in winter) supports the largest open berry shrubfield in the ski area and can attract up to 45 different bears from August to October.

Large males are currently dominating this huge berry supply by confronting mothers with cubs and younger males. Usually a few single, adult females can forage within 40 metres of males because most males won't spend too much effort harassing potential girlfriends or mothers. But over the last week, Olivia, a middle-aged pregnant bear, is the only female to be seen sneaking in to take advantage of the heavy berry concentration. Jeanie, the largest female bear in Whistler, has always been seen using the field because most males will back off from her approach. But this season, so far, is the first time I have not seen her using Greenacres from mid-August to mid-September. It doesn't mean she hasn't, but it indicates she has dropped significant use of the area.

The presence of aggressive males might indicate that berry availability across the landscape is thin and dominant bears are trying to improve foraging efficiency by taking over heaviest concentrations. Male aggression is typically the highest during the late May to late July breeding period but this year was low, resulting in 100 per cent cub survival. It probably helped that we had more girlfriends than mothers (who don't breed when they have cubs).

However, since mid-August Alice, a dominant mother, has lost one of two cubs. I think the cub is still alive but separated, as two different bear viewing guides have seen the same lone cub. Cubs can be separated for some time with a good chance of reuniting with their mother.


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