Home Sweet Temporary Home: Patch Use by Unpaired Gray Hawks in a Highly Fragmented, Rapidly Changing Landscape.

Urban development and land-use changes are fragmenting, degrading, and destroying wildlife habitats worldwide. In the rapidly developing Lower Rio Grande Valley of South Texas, USA, the Gray Hawk (Buteo plagiatus) must navigate a matrix of cultivated and urban areas with limited native vegetation. The long-term persistence of the Gray Hawk in this landscape depends heavily on unpaired hawks successfully locating and establishing territories—a process that requires extended exploratory movements. Using GPS telemetry, we tracked the movements of 30 unpaired Gray Hawks (14 males, 16 females) until they settled in breeding territories or their transmitters stopped functioning. Gray Hawks utilized 625 distinct habitat patches, with 7359 total visits to those patches, including 3142 return visits. We observed sex-based differences in patch use. Males occupied patches with more grassland/herbaceous areas, while females occupied patches with slightly more tree cover and water. Despite these differences, resource selection models revealed both sexes primarily selected habitat based on structural complexity, particularly tree height variability, rather than specific land cover types. Nearly 63% of patches (n = 392) showed spatial overlap between individuals, with 22 pairs documented within 100 m of each other during the same hour. These findings underscore the importance of preserving small, structurally diverse resource patches across fragmented landscapes, as they serve as critical temporary settlement sites for unpaired hawks. Effective Gray Hawk conservation in the Lower Rio Grande Valley must focus not only on protecting breeding territories, but also on maintaining the network of smaller patches that support movement and temporary settlement of unpaired individuals. [ABSTRACT FROM AUTHOR]