Resource Partitioning among Three Buteo Species in the Centennial Valley, Montana

Abstract

Birds most commonly partition resources along habitat dimensions, followed by food, then temporal dimensions (Cody 1974, Schoener 1974). Studies in Alberta (Schmutz et al. 1980), Oregon (Cottrell 1981), and Washington (Bechard et al. 1990) reported partitioning of nesting habitat among Red-tailed (Buteo jamaicensis), Ferruginous (B. regalis), and Swainson's Hawks (B. swainsoni) while broad overlap occurred in prey use and nesting chronology. One species was much less common than the other two in each of those studies. In contrast, these closely related hawks coexist in equal abundance in the Centennial Valley, Montana. Do mechanisms that allowed coexistence in previous studies operate in areas where these hawk species are equally abundant? The objective of this study was to determine if and how these hawks partitioned habitat, food, and temporal resources in the Centennial Valley.