Movement patterns and home ranges of male and female Snowy Owls (Bubo scandiacus) wintering on the Canadian prairies

Abstract

Meeting energy requirements during the nonbreeding season is important for many animals and some defend winter territories to secure a food supply. In birds of prey, females, the larger and competitively dominant sex, may monopolize areas with higher prey abundance than males. We thus predicted that female Snowy Owls (Bubo scandiacus (Linnaeus, 1758)), which might acquire the high-quality habitats and individuals in better body condition, would be able to persist on smaller home ranges, travel shorter distances, and spend proportionally more time on a home range than males, during the winter. On the prairies in central Saskatchewan, we deployed satellite transmitters on 11 male and 12 female Snowy Owls over two winters. There were no significant differences between the sexes in home-range size or the amount of travelling during the winter months. Mean first home range (95% minimum convex polygon) size was 54.4 km2 for males, 31.9 km2 (estimated marginal means) for females, and 53.8 km2 for the sexes combined. However, within sexes, home-range size was negatively correlated with body condition as predicted. A lack of defense of home-range perimeters against conspecifics could increase variation in home-range size and movement patterns and reduce differences between the sexes.