Broad-Winged Hawk Nesting and Food Habits

Abstract

COMPARED to the literature on other species of raptors, relatively little has been published on the Broad-winged Hawk (Buteo platypterus). Although clutch size (Burns, 1911) and food habits (May, 1935, and others) are well-documented in this species, little information is available on fledging rates and nesting densities. Similarly, reports on Broadwing ecology in the northern part of their breeding range are scarce. This paper describes the nesting density, productivity, and food habits of a breeding population of Broad-winged Hawks near Rochester, Alberta. Central Alberta, the locale of this study, is on the northwestern fringe of the Broad-winged Hawk range in North America (Burns, 1911; May, 1935; Bent, 1937). Reptiles and amphibians, which are important components of this hawk's diet in more southern latitudes, are scarce in central Alberta. We were especially interested in the incidence of these prey items in the Broad-wing diet in our area, and in evaluating the possibility that their scarcity limits the northern distribution of this raptor.