Breeding performance is explained for coloniality and phenology but not for urbanization in a generalist raptor bird

Abstract

Urban sprawl is recognized to homogenize biota, with several species that fail to adapt to these new human scenarios. However, some species can live and breed successfully in urbanized habitats. We compared the breeding performance of the relatively common raptor and poorly studied, chimango caracara (Milvago chimango) in an urban gradient of central Argentina. Breeding data of 359 nests were collected during breeding seasons from 2010 to 2012. Birds nested in colonies of 3 – 75 pairs. Overall breeding success was 49.9% with productivity at 1 ± 1.14 chicks per nest. Models revealed that reproductive success and productivity were higher in nests with earlier laying dates and sited in larger colonies and that urbanization gradient did not affect either reproductive output or laying day. Urban habitats in central Argentina appear to provide similar reproductive success of chimango caracara than rural or natural habitats. Thus, chimango caracara shows behavioral plasticity for their successful persistence to human changes as reflected in successfully breeding in a wide variety of habitats such as natural, rural, and urbanized environments that have been impacted by humans.