Diet of Grey Wolves (Canis lupus) During Calving in a Moose– Caribou System in Northern Ontario

Grey Wolves ( Canis lupus ) are a leading proximate cause of declining populations of Woodland Caribou ( Rangifer tarandus ), a threatened species. Although predation on adult caribou has been well documented, less is known about predation on neonatal calves. We used scat analysis to examine the diet of wolves in an area of Ontario overlapping the receding southern limit of caribou occurrence. Wolves consumed mostly Moose ( Alces americanus ; 82.7%), followed by American Beaver ( Castor canadensis ; 10.9%), caribou (3.1%), and Snowshoe Hare ( Lepus americanus ; 1.5%). This low use of caribou is consistent with other evidence suggesting that caribou are a minor dietary component of wolves in this system; however, because most caribou consumption consists of calves, the impact on this slowly reproducing species may still be significant.