Breeding Home Range and Nest Site Fidelity in Broad-winged Hawks (Buteo platypterus) in North-Eastern U.S.A.

GALLEGO, DIEGO; MCCABE, REBECCA; GOODRICH, LAURIE

Fort Lauderdale

Congreso; Annual Meeting of the Raptor Research Foundation; 2022

Raptor Research Foundation

The Broad-winged Hawk is a small buteo that breeds in deciduous or mixed-deciduous forests of northeastern and northcentral North America. Although it is conspicuous while in migration, its secretive behavior while nesting makes it difficult to understand its habitat needs during the breeding season. We assessed breeding home range size for broad-winged hawks in northeastern U.S.A., and we tried to relate them to sex, ecoregion, and nest success and productivity. Seven adult females and three adult males were tracked using GPS transmitters during spring and summer 2015 to 2021. We used autocorrelated kernel density estimation (AKDE), which models the autocorrelation structure of tracking data and therefore performs more accurate predictions of the home range. Core home range sizes (50% estimator) averaged 0.76±0.60 km2 in females and 7.49±3.48 km2 in males. Breeding home ranges (95% estimator) were almost 10 times bigger (P0.85 for most cases) indicating a strong nest site fidelity. Moreover, inter-annual distances of nests from the same individuals were 243.41±354.93 m (Range: 0.00-759.05). This is the first study assessing breeding home range areas of this secretive hawk. Our findings indicate that Broad-winged Hawk ranges may remain stable over several years if the conditions are appropriate for them to breed (e.g., food availability, or competition). The knowledge and protection of core areas where Broad-winged Hawks breed is key for their long-term conservation.