Urban areas promotes shifts in the proportion of prey consumed by four raptor species (Accipitridae) in Mexico.

Background: Urbanization is a process of environmental change which reduces and fragments the original habitat and creates new pressures, conditions, and resources for the species. The urban areas act as an ecological filter, which may exclude species, while others can colonize and thrive in cities, generating a process of biotic homogenization. As top predators, the changes in prey community composition could affect the diet of raptors. However, this effect has been understudied. Methods: In this study we compiled information about the frequency of prey consumed by Cooper's Hawk, Common Black Hawk, Roadside Hawk and Gray Hawk using two sources of information: (1) data extracted from photographs available on citizen science platforms and (2) a search of scientific literature. Using these data, we compared the diet composition, the proportion of prey consumed and the trophic niche breadth by four species of raptor in urban and non-urban areas. Additionally, we evaluated whether the variability in frequency of predation records by raptors was associated to the type of prey or their breeding season. Results: Our results indicate that the raptors studied consumed at least 91 prey species in Mexico. Most records of predation by Common Black Hawk, Roadside Hawk, and Gray Hawk occurred in non-urban areas. On the contrary, most records of predation by Cooper's hawks occurred within urban areas. There was no statistical difference in the richness of prey consumed by Cooper's Hawk and Gray Hawk between urban and non-urban areas. In contrast, fewer prey types were consumed by Common Black Hawk and Roadside Hawk in urban areas than in non-urban areas. The proportion of prey types consumed in urban and non-urban areas was significantly different for Cooper's Hawk, Roadside Hawk and Gray Hawk. Conversely, the proportion of prey types consumed by Common Black Hawk's was similar in urban and non-urban areas. The four raptors studied increased the proportion of birds consumed in urban areas by between 2% and 36%, regardless of their preference for a specific type of prey. The trophic niche breadth of raptors was broader in urban areas than in non-urban areas, except for Cooper's Hawk, which had a narrow trophic niche breadth in urban areas than in non-urban areas. The temporal variation in the frequency of predation records was influenced by differential factors such as the breeding season, the type of prey consumed, and the utilization patterns of citizen science platforms. Our results demonstrate that the four raptors studied increased the proportion of bird consumption in urban areas. This shift in raptors' diets could be linked to the increased prevalence of diseases transmitted by feeding on infected birds in urban areas. This emphasizes the importance of conducting research to assess the prevalence and transmission rates of diseases that could threaten the conservation of birds and raptors in urban areas.