Black Bear Researcher
As a 50-pound, 18-month-old yearling black bear leaves its mother it enters a world of challenges from other bears and human. After being pushed from the security of their mother, yearling (1-year-old) black bears experience the greatest mortality of all bear classes (cub, yearling, sub-adult, adult).
As cubs-of-the-year (COYs), their survival rate is around 90 per cent. After family break-up the survival rate of females drops to 70 per cent and males to 50 per cent.
Lacking the dominance and experience of an adult male or female, yearlings represent the "teenage" phase in a bear's life. Sub-adult bears ( < 4 years) must establish themselves physically and mentally. Below is a chronological outline of events a male and female yearling faces upon separation from their mother:
Year 1 - Leaving Mom
Whistler black bear females rear cubs for 17-19 months.
Mother breaks up family during June through July in response to the presence of males for mating.
She walks away from yearlings - they attempt to follow and she charges.
Break-up occurs during 1-10 days as yearlings attempt to reunite with their mother.
Siblings (brother and sister) may remain together or separate, reuniting occasionally.
Siblings remain in natal range (mother's territory) and may den together.
Year 2 - Sibling Support and Finding Food
Sons may or may not move from natal range depending on pressure from dominant bears.
Daughters remain in natal range - mother moves away allowing her daughter food resources and space.
Siblings may continue to reunite around concentrated foods (dumps or berry shrub fields).
Sons are more likely to move into human areas to avoid dominant males and families.
Year 3 - Tolerating People
Sons move into human development fringe to secure enhanced food (natural and human) and avoid competition from dominant bears.
Sons can establish themselves within Whistler valley as vacancies are created from destroyed bears.
Females may use human development habitat if close to natal range.
Males become sexually mature at 3.5 years but mating success is low due to competitive dominant males.
Daughters continue occupying natal range, often overlapping feeding, bedding, and denning activities with mother.
Year 4 - Young Adults
Males emerge from dens sexually mature and begin following female scent trails during late May.
Males remain established in Whistler or continue to disperse up to 100 km.
Majority of bears destroyed in Whistler have been males (personal communication BC Environment Conservation Officer Service, Squamish, 1994-2001).
Females become sexually mature if body reaches required fitness (food availability).
Five year old daughters emerging with first litter may shift from their mother's territory to establish their own.
Yearling Bears - Part 2 will report 2001 mother-yearling groups and habitat quality influence on weight gain, development, and survival.
The next Sea-to-Sky black bear slide presentations are in Whistler on May 31 at the Fairmont-Chateau and in Squamish on June 6 at the Squamish Public Library. Presentations are from 7-9 p.m.
Bear Update columns are sponsored by Pique Newsmagazine. Questions or information about black bears call the Whistler Black Bear Project at 604-898-2713 or by e-mail mallen_coastbear@direct.ca
