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Bear update: Spring forecast

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Based on 2016's spring count, I'm expecting at least 33 adult black bears in the Whistler valley plus the ski area this spring: 16 adult males and 17 adult females. 

Of the 17 adult females, 13 were observed in breeding pairs last June to mid-July and four were with cubs of the year (COY) — and despite 2016's early berry ripening (thanks to a warmer spring) coupled with a sudden temperature drop through June leading to a scattered flower-kill and the end of berries in early September, most females still without cubs by early October, appeared in adequate pre-denning condition.

Mean litter size is around two cubs, so the 2017 forecast range is 13 to 26 cubs from 13 possible mothers. Two of the 13 females, Olive (mother Olivia) and Brittany (mother Brownie) in the ski area have never produced cubs, as there are usually two to three years of breeding before a first litter is produced.

If the population does experience high numbers of cubs, mortality may also be high (50 to 60 per cent) because the number of non-breeding mothers (with COY) will be higher. This may force adult males — especially young adults — to increase their frequency of aggressive encounters toward non-breeding mothers. Cubs are killed by non-related males as a way of forcing their mothers into breeding.

Female black bears normally only breed every second spring and each spring each female typically experiences a different breeding cycle. In 2016, the population did lose one adult female, a Blackcomb resident. Michelle and her two cubs were destroyed at Lost Lake Park after mountain bikers conflicted with her habitat use along Lost Lake Park trails.

Another valley mother and one of two cubs were translocated — the other cub was killed in the handling of the family.

South of the population near Brandywine-Brew area, a mother black bear was struck by a vehicle on Highway 99 (and later destroyed by wildlife officials) during the Ironman weekend. Her two cubs were sent to wildlife rehab. 

Cub survival in 2016 was 40 per cent — six of the 10 cubs counted were lost. Three cubs died as a result of human conflicts and three were killed during frequent male aggression toward families during the breeding period.

A network of cameras is being set up for the spring bear census during May and June. These cameras are motion- and thermal-triggered. They identify bears along trails of movement, at creek crossings, in daybeds, and in concentrated grazing areas. Thanks to Whistler-Blackcomb, Whistler Sliding Centre, and the Fairmont Chateau Golf Course for allowing non-invasive cameras to be set up. Cameras are not placed near areas frequented by people, but, if people are close by, a camera sign is set up.

Currently, green-up is slow and lightly scattered throughout the valley. Mid-mountain ski slopes remain covered with heavy snowpack, so expect high bear activity (grazing green-up) in the valley through May and to at least mid-June. Valley huckleberry phenology is behind three to five weeks. Plant development may speed up through May with forecasted warmer temperatures but, high elevation (greater than 1,400 metres) berry ripening/production for August and September will be negatively impacted by the current 300-plus-centimetre snowpack and continued cooler temps.

My longest-known (about 20 years) male black bear "Slumber" was sighted on April 24 by a friend of mine, and we subsequently, confirmed his identification on April 25.

Slumber stopped foraging berries in first week of September 2016 due to an early ripening, a flower kill during June bloom, and thus an earlier "drop" in berries. 

It always amazes me that a 200-kilogram black bear can sustain itself on clover for 40 days especially during the pre-denning phase of hibernation.

What I'm finding is bears seem to have an "annual" nutrition and a "life" nutrition. The annual nutrition is supported by the previous plus current year's food sources. 

The life-nutrition possibly is a reserve system built upon by years of good health that allows an individual bear to survive a season, or back to back seasons of poor food supply. 

Similarly, females that produce large litters of cubs following poor berry years — these females are likely operating at a higher nutritional plane supported by better life-nutrition and/or genetic lineage. 

As of April 30, there are at least 10 black bears active in Whistler Valley: five adult males (one is tagged), one adult female plus one yearling, and three sub-adults.

No bears have been seen along the highway between Squamish and Whistler nor in the Callaghan, but there are bears slowly becoming active along both transportation corridors. Use caution driving during twilight.

My bear studies, now in their 24th year, are unofficial and self-funded. I work as a guide and lecturer. For questions contact me at mablackbearstudies@gmail.com

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