Skip to content
Join our Newsletter

Bears competitive in hunt for berries

Aggressive males may make life difficult for mothers, cubs
64085_l

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.

And since early September two mothers, Elly and Brownie, have each lost one of two cubs, likely to male aggression.

In the second week of September a local photographer witnessed from a moving Whistler gondola a large bear on top of a cub that was previously fleeing with its mother and sibling out of a berry field. The next day Elly was located with just one cub.

Excluding the breeding period, male bear aggression seems to be highly opportunistic. Normally, post-breeding behaviour is food consumption and weight gain for winter - bears don't want to spend the energy dealing with each other. But, if males are feeding close to families within concentrated berry patches the evolutionary tactic of male behaviour dictates that they "take a run" at killing the cubs.

If cubs are killed it can still promote the mother to shift biology and breed, or the cubs could - as has been reported elsewhere in B.C. and North America - be eaten.

The large dominant males are not normally that aggressive to families because they most frequently father cubs. It's the younger adult males that are competing with these alpha males to secure breeding success and elevate their status.

As of Sept. 18, the seven mothers with a total of 13 cubs in the ski area are now down to 11 cubs, including one cub separated from its mother. The cub has been seen many times and is so far feeding and keeping to the trees for security.

In the early afternoon of Sept. 18 during heavy rain and fog, Zoe, a Blackcomb resident that comes over to Whistler's northslope berry patches, was confronted by Slumber, one of the largest (400+-lbs.) male bears in Whistler. Her cubs were treed 25-metres up an old growth mountain hemlock. Zoe tried to hold her ground but her defensive threats against Slumber were ignored. Slumber kept feeding and scenting within 10 metres of the base of the tree with the cubs. Zoe circled around him charging from different angles.

To make matters more stressful, Skinner, another large male (and more aggressive) arrived but kept his distance from Slumber. Skinner eventually left and Slumber was suddenly scared away by the sound of squealing bike brakes somewhere in the surrounding fog. A lone mountain biker had apparently got lost in the fog and came barreling down right beside the Greenacres berry field startling Slumber who immediately bolted into the berry patch and headed upslope away from the bear family.

It's hard to predict what Slumber would have done; he was much too large to have climbed to the height of the cubs because the trunk would have been too small to support his weight. Slumber is not normally that aggressive. Many times males merely "inconvenience" a mother by hanging around and feeding close to send the message that they are around. But then again, there is always opportunity.

Bears should have berries through mid-October but still many younger bears will be struggling to gain weight and thus push their behaviour in search of human foods to supplement weight gain. Most bears look fat but still have 40+ days to go before denning; a lot can happen in that time.

If anyone has questions about their sightings they can e-mail mallen_coastbear@direct.ca