Multiscale Habitat Selection of Gray Hawks (Buteo plagiatus) in South Texas
Gray Hawks are facing increasing pressure from habitat loss and land fragmentation in South Texas, where they're at the edge of their U.S. range. To understand what these birds need to thrive, we tracked adults and fledglings to study which habitats they prefer—both within their home ranges and for their nest sites. We found that Gray Hawks consistently chose areas with tall trees, dense vegetation, and a mix of tree heights, while avoiding open spaces like grasslands and bare ground. Surprisingly, even urban areas with mature trees served as valuable habitat, offering some refuge when natural areas are limited. These findings show that protecting wooded areas—whether along rivers or in city parks—is vital to supporting Gray Hawk populations in changing, human-dominated landscapes.
Gray Hawk activity across an urban heat gradient: Rhythmic stability, behavioral flexibility
Urban growth and climate change are transforming natural habitats, creating challenges for wildlife living in cities. In South Texas, we used GPS tracking to study how Gray Hawks respond to these pressures. By monitoring 35 individuals, we found that hawks didn’t change the timing of their daily activity across urban and rural areas—but they did become more active in hotter, more developed environments, especially during extreme heat. Interestingly, human routines like commuting or weekend recreation didn’t seem to affect hawk behavior. These results suggest that Gray Hawks cope with urban and thermal stress by increasing their effort rather than avoiding people. Our work highlights how raptors can adapt to cities and why thoughtful urban design is important for supporting native wildlife.
Movement effort in Gray Hawks across a fragmented,high-temperature landscape: Environmental and seasonal drivers
Climate change and urbanization are reshaping the landscapes Gray Hawks rely on in South Texas. To understand how these raptors cope, we tracked 63 individuals year-round and analyzed over 400,000 GPS points to measure how much effort hawks invest in movement. We found that hawks moved more—especially with longer steps and straighter paths—when exposed to both heat and urbanization, suggesting higher energetic costs under these stressors. Tree cover and diverse vegetation helped reduce effort, buffering hawks from extreme conditions. While unpaired birds responded consistently to heat, territorial adults varied widely in their sensitivity to temperature and development. These results show that movement effort increases gradually in response to environmental stress, not suddenly, and that hawks adjust their behavior in subtle but meaningful ways. By revealing how and when movement becomes costlier, this study offers new insight into how animals may persist in fragmented, warming environments.
Gray Hawk Movement Ecology
Over the past five years, my research has focused on the movement ecology of Gray Hawks (Buteo plagiatus) in the Lower Rio Grande Valley of Texas, combining high-resolution GPS tracking with spatial modeling and behavioral analysis. This work has explored juvenile dispersal, adult home range size, patch use, and response to a wildfire in a fragmented landscape. I am currently examining behavioral flexibility in relation to urban heat gradients, activity rhythms, seasonal shifts in movement behavior, the energetic costs of movement under thermal and landscape stress, and landscape-scale habitat suitability using species distribution models. Collectively, these studies constitute one of the most detailed movement datasets available for a raptor at the northeastern edge of its range and offer insight into how individuals navigate human-dominated environments under climate pressure. My current work builds on earlier findings to develop a broader conservation framework, with an emphasis on identifying habitat and behavioral thresholds relevant to management, restoration, and climate adaptation planning.