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Bear Update: Spring bear forecast and education programs



Black Bear Researcher

Den emergence, yearling survival, and cub forecast

The window of den emergence for bears is April. A few bears emerged in early March as a result of the mild, early to mid-winter. Significant snowfalls above mid-elevations during March, however, may have been adequate to keep bears in a secured denning state, unaware of changes in temperature and precipitation. If den entrances are efficiently covered, occupants will not feel ambient conditions as fast. Snowfalls of March likely prevented more bears from emerging earlier.

April will see lone adults and sub-adults begin emerging first, followed by mothers with yearlings (16-month-old cubs) by mid-late April and mothers with COY (cubs-of-the-year) during early to mid-May. Yearlings remain with mothers until late May to late June, when mothers force separation to begin subsequent courtship. The cause of many bear/human conflicts in Whistler stems from this dispersing sub-adult bear-class striving to forage and survive while avoiding dominant bears.

Survival rate of cubs after their first hibernation (with their mother) and emergence as yearlings to 19-months is high (95 per cent). An 11-month-old cub enters the den at 30 to 50 kg and will emerge having lost 10-50 per cent of its body weight. Emerging 16-month yearlings may be of two sizes: the smaller "border collie-size" and the larger "German shepherd-size" both with "Mickey Mouse" ears.

The first four years of a bear’s life post-parental care are extremely tough. Yearling survival will be determined later this month at or near den emergence as five mothers are expected with yearlings and six expected with cubs. There are potentially a minimum of 11 yearlings to disperse through Whistler Valley.

The spring forecast for new-born cubs is considered low due to the poor 2002 berry crop. Drought conditions limited berry size and extended drought increased onset of shriveling. Smaller berries limit bear foraging efficiency and lower berry feeding days, reducing potential weight gain. Some female bears, however, were gaining weight. Females may expand movements to other berry habitats along the edge or outside of their territories and/or try to exploit human food to supplement the natural food shortage. Single cub litters may be the norm for this spring.

BBC Bear Documentary

I am advising on and partially filming for a second documentary on black bears in Whistler by the BBC Natural World (Bristol, UK). The theme of this film will be mother and daughter black bears – their behaviour, biology, and activities pre- and post-family break-up, including using a thermal imagery camera on denning bears this fall. Filming will be guided by the Whistler Black Bear Project in the Whistler-Blackcomb ski area and Whistler Interpretive Forest. Raw footage obtained from the first BBC bear film In the Company of Bears has made a vital contribution to the effectiveness of local bear education programs.

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