Effects of collection method on sex and age composition of black bear (Ursus americanus) harvest in Oregon
Kohlmann, Stephan G.
Green, Richard L.
Trainer, Charles E.
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We investigated sex and age distribution of 5168 black bears (Ursus americanus) harvested or live-trapped in Oregon from 1983 through 1994. Successful hunters were asked to submit a lower premolar tooth along with information on date, management unit, sex of the bear and method of take (i.e., using hounds, bait stations or stalking). In addition, we used capture records and tooth samples of bears snared following complaints of damage or live-trapped in two research studies. Tooth collections of hunter-harvested bears represented 5% to 58% of the annual harvest, as estimated from standard hunter phone surveys. Using data from all years, we compared frequency of sex and age classes according to method of harvest (i.e., hounds, bait, stalking, damage removal or live-trapping). More that 60% of bears harvested were males. Hunting with hounds accounted for >50% of the total harvest. Hunting method affected the proportion of males taken. The median age of bears harvested using hounds wasgreater than for baiting and stalking. Bears from damage removals and the live-trapped sample were older than those taken by stalking and while using bait stations. Our samples indicate different vulnerabilities of the sexes to different collection methods. Vulnerability ratio coefficients for male bears (compared with females) ranged from 1.46 (bait) to 1.12 (damage removals). We conclude that bear harvest data have a considerable age and sex bias, depending on collection methods used. This is likely to confound estimation of effects of changing harvest strategies, such as the prohibition of certain hunting techniques