Habitat use by parturient and nonparturient caribou of the Mentasta caribou herd

Abstract

I compared habitat use and diet characteristics among preparturient female caribou (Rangifer tarandus), and between parturient and nonparturient caribou during and after parturition, in the Mentasta Caribou Herd, Alaska, to explain movements by parturient females just prior to giving birth. I monitored 39 radio-collared females in 1994 and 40 animals in 1995. I estimated forage biomass, collected forage for determination of nitrogen and in-vitro dry matter digestibility (IVDMD), and collected fecal pellets to calculate indices of diet composition and diet quality at sites used by caribou. I also recorded sightings of predators throughout the study area. During peak parturition, females with young used habitat with fewer predator sightings, a lower abundance of forage species, but with nearly equal forage quality as that used by females without young. I hypothesized that parturient females used birth sites that lowered the risk of predation, and did so at little cost nutritionally.