Winter severity and wolf predation on a formerly wolf-free elk herd

We studied wolf (Canis lupus) predation on elk (Cervus elaphus) in Yellowst one National Park from 17 March to 15 April 1997 (severe winter conditions) and from 2 to 31 March 1998 (mild winter conditions) 2-3 years after wolve s were reintroduced to the park. Elk composed 91% of 117 kills. Data compar isons for 1997 versus 1998 were: hunting success race, 26% versus 15%; kill rate, 17.1 kg/wolf/day versus 6.1 percent of kill consumed in first day, 7 versus 86; percent femur marrow fat of adult kills, 27 versus 70: calf.-ad ult ratios of kills, 2:33 versus 17:23; sex ratio of kills. 14M:19F versus 17M:6F; mean age of elk killed, males 6.1 years, females 15.2 versus males, 4.8, females 13.0. Winter severity influenced the wolf-elk relationship mo re than the naivete of the elk herd to predation by wolves.