Prevalence of Pathogens in Free-living Adult Chimango Caracaras (Milvago chimango) in Three Areas with Different Levels of Urbanization in the Pampas Ecoregion, Argentina

Abstract

Urbanization can adversely impact animal populations through factors such as loss of natural habitat, introduction of nonnative competitors and predators, pollution, and increased exposure to pathogens. Because they are top predators, raptors are considered good indicators of ecosystem health. However, there is limited information about how environmental factors associated with urbanization can alter raptors’ susceptibility to pathogens. We evaluated exposure to selected pathogens of the Chimango Caracara (Milvago chimango), a generalist and opportunistic species endemic to South America. This species is distributed over a wide range of environments, including urban areas, and often takes advantage of human-generated resources such as domestic waste, urban garbage, and carrion, potentially increasing its exposure to pathogens. We captured adult Chimango Caracaras in three areas that varied in level of urbanization, in the southeastern region of the Buenos Aires Province, Argentina. Captured individuals were tested for exposure to Bacillus anthracis, Salmonella spp., and Trichomonas spp. All individuals tested were negative for these pathogens. Whether this represents a true lack of exposure to these microorganisms, the ability of this raptor to effectively inhibit the colonization of the gastrointestinal tract by these microorganisms, or an inability of the pathogen to colonize the Chimango Caracara’s gastrointestinal tract remains to be determined. This is the first study to assess the prevalence of selected pathogens in Chimango Caracaras inhabiting areas with different levels of urbanization.