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

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, Rangifer tarandus granti, movements, disturbance, insect harassment, Prudhoe Bay, petroleum developmentLes mouvements et activités du caribou (Rangifer tarandus granti) sont comparés prés de deux sites de forage actif dans la périphérie du champ de pétrole de la baie Prudhoe ainsi que dans un site de contrôle. Les caribous dans les sites expérimentaux et de contrôle présentaient un taux de mouvement et un régime d'activité semblables, mais on observa un bon nombre de réactions localisées aux routes, aux pipelines, à la circulation de véhicules et à d'autres structures et activités. Les tourments infligés par les insectes ont eu un effet appréciable sur les mouvements et le régime d'activité. Les groupes tourmentés par les insectes se déplaçaient environ deux fois plus vite que les groupes non tourmentés, et passaient environ 50% moins de temps à se nourrir et à se reposer que ces derniers. Des 99 groupes ayant approché une route, un pipeline et/ou un site de forage 70.7% traversaient directement, 19.2% faisaient un détour autour du site de forage, et 10.1% faisaient demi-tour et quittaient le champ d'étude. Aucune preuve n'a indiqué que les vaches et les veaux des caribous évitaient la région à cause des travaux de forage.Mots clés: caribou, Rangifer tarandus granti, mouvements, perturbation, les tourments infligés par les insects, la baie Prudhoe, developpement de l'industrie pétrolifèr

Predicting energy expenditures for activities of caribou from heart rates

Highly significant (P<0.001) linear relationships between oxygen comsumption (VO2) and heart rate (HR) were found for six caribou (Rangifer tarandus grand) at several times during the year. The standard error of the estimate for predicting VO2 from HR was within 10% of the mean VO2 for 9 of 13 caribou/season combinations. Energy expenditures by caribou while feeding on grain at a trough, grazing, browsing and walking within a large enclosure were 12%, 17%), 18% and 46% higher than the cost of standing. HR's recorded during a given activity decreased sharply during September and October, and reached a minimum in January. An abrupt increase in HR's of female caribou occurred 3 weeks prior to parturition. Heart rate telemetry can be used to determine the relative energy expenditures of free-ranging caribou with reasonable accuracy