Movements and Activity Budgets of Caribou Near Oil Drilling Sites in the Sagavanirktok River Floodplain, Alaska

ABSTRACT. Movements and activity patterns were compared for caribou (Rangifer tarandus granti) near two active drilling sites on the periphery of the Prudhoe Bay oilfield and for caribou from a control site. Caribou on the experimental and control sites had similar movement rates and activity budgets, but many localized responses to the roads, pipelines, vehicle traffic, and other structures and activities were observed. Insect harassment had an appreciable effect on caribou movements and activity budgets. Groups harassed by insects moved approximately twice as fast and spent at least 50 % less time lying and feeding than did unharassed groups. Of the 99 groups that approached a road, pipeline, and/or drill site, 70.7 % crossed directly, 19.2 % detoured around the drill site, and 10.1 % reversed direction and left the study area. No evidence was found that caribou cows and calves were avoiding the area because of drilling operations. Key words: caribou, Rangqer tarandus granri, movements, disturbance, insect harassment, Prudhoe Bay, petroleum development RÉSUMÉ. Les mouvements et activitts du caribou (RangifPr tarudus grunti) sont comparks prks de deux sites de forage actif dans la @riphtrie du charnpde @role de la baie Prudhoe ainsi que dans un site de contrôle. Les caribous dans les sites expkrimentaux et de contrBle prksentaient un taux de mouvement et un rtgime d’activitk semblables, mais on observa un bon nombre de rtactions localisdes aux routes, aux pipelines, 21 la circulation de vthicules et B d’autres structures et activitks. Les tourments infligts par les insectes ont eu un effet apprkciable sur les mouvements et le rtgime d’activitt. Les groupes tourment & par les insectes se dtplaçaient environ deux fois plus vite que les groupes non tourment&, et passaient environ 50 % moins de temps B se nourrir et b se reposer que ces derniers. Des 99 groupes ayant approcht une route, un pipeline et/ou un site de forage 70.7% traversaient directement, 19.2 % faisaient un dktour autour du site de forage, et 10.1 % faisaient demi-tour et quittaient le champs d’ttude. Aucun