Influence of agricultural intensity and urbanization on the abundance of the raptor chimango caracara (Milvago chimango) in the Pampean region of Argentina

Chimango caracara (Milvago chimango) is a southern Neotropical species and the most common raptorial bird in the Pampean region of Argentina, where natural grasslands were completely transformed by agriculture and urbanization. We determined whether this species responds to the intensity of these human disturbances through changes in its abundance. To examine the response to agricultural intensity, both birds and land use were surveyed along 18 transects covering the regional agricultural gradient from pure arable to pure pastoral farming landscapes. To explore the effects of urbanization, birds were surveyed at 19 points along an urban-rural gradient. Results showed that chimango caracara did not respond to changes in agricultural intensity. No land use type was associated, either positively or negatively, with abundance in the arable or pastoral farming scenarios. In contrast, we observed a negative response to increasing urbanization, where a higher abundance was recorded in rural than in commercial or residential areas.