Caribou distribution during calving in the northeast National Petroleum

Abstract: Barren ground caribou (Rangifer tarandus granti) of the Teshekpuk Caribou Herd (TCH) inhabit the western por-tion of Alaska's Arctic Coastal Plain within the National Petroleum Reserve—Alaska (NPR-A). Alaska's North Slope com-munities, management agencies, and private industry are interested in this herd because of its importance as a subsistence resource and location relative to potential petroleum development. From 1998 through 2000, we monitored caribou dis¬ tribution during the calving period within the Northeast Planning Area of the N P R- A using systematic strip-transect aerial surveys, as well as V H F and satellite telemetry for cow caribou. Aerial survey and telemetry data indicated cows with calves were distributed around Teshekpuk Lake, with a concentration south of the lake in 1999 and 2000. Inconsistencies in weather conditions, survey timing (both strip-transect and V H F surveys), 100 % coverage survey areas, and small sample sizes confound interpretations of our results. However, several patterns were apparent. Later transect survey timing (7—12 June versus 4—7 and 5—8 June) resulted in more cow/calf pairs recorded. Our 18 % coverage area, orig-inally based on V H F telemetry data for the extent of T C H calving, covered a consistently high proportion (95 % to 100%) of the annual calving ranges (95 % kernel utilization distributions), but accounted for only 24 % to 46 % of the adult cows in the T C H based on the current Alaska Department of Fish and Game population estimate (1999) and average 1998¬ 2000 herd composition. It appears that either our transect survey methodology significantly underestimated the true number of caribou cows in the study area, many cows calved outside the area or moved into the area and calved after ou