Prey selectivity of wolves in Banff National Park. II. Age, sex, and condition of elk

Wolf predation on elk was studied in Banff National Park, Alberta. Overall, wolves took a higher proportion of adult males and calves than occurred in the population. However, wolves encounter elk as herds rather than individuals, and when the herd is considered to be the unit of available prey, calves are highly selected for compared with both adult males and females. Adult elk killed by wolves were older than those killed on the road or railway, but a simple model showed that this result can be caused by a bias in obtaining the population age distribution from a mortality source. Jaw lengths and antler characteristics of wolf kills did not differ from those of road and rail kills. Adult elk, but not calves, killed by wolves had lower reserves of marrow fat than elk killed on the road and railway.