Health Assessment of Three Species of Free-Living Raptors Inhabiting a Pampas Agroecosystem in Central Argentina

The Pampas Grasslands ecoregion of central Argentina has been dramatically transformed since the arrival of agriculture in the late 18th century. Currently, <10% of this ecosystem remains in its native state and <1% is protected. At least 14 species of Accipitriformes, four Falconiformes, and four Strigiformes are found in the Pampas agroecosystems. We investigated the health status of three raptor species inhabiting the Pampas agroecosystems of Melincué, Santa Fe province, central Argentina: 13 Roadside Hawks (Rupornis magnirostris), 17 Chimango Caracaras (Milvago chimango), and 21 Burrowing Owls (Athene cunicularia). Our goal was to assess the physical condition and the prevalence of exposure to parasites and common avian pathogens of free-living raptors. All birds were caught with bal-chatri traps and were in good body condition except two Burrowing Owls. All three species exhibited a low prevalence of exposure for Salmonella Pullorum/Gallinarum, Mycoplasma gallisepticum, Mycoplasma synoviae, Bacillus anthracis, and Chlamydia spp. Prevalence of chewing lice (Mallophaga) was 28.6% for Burrowing Owls and 5.9% for Chimango Caracara. Hemoparasites (Haemoproteus spp.) were found only in Chimango Caracaras, with a prevalence of 21.4%. Based on physical findings, low prevalence of exposure to common avian pathogens, and hematology and biochemistry results within normal limits based on published literature, raptors in our study appeared to be in overall good health condition in 2000–2001. Although not exempt from being exposed to some pathogenic and non-pathogenic microorganisms, our results support the hypothesis that, in Pampas agroecosystems, these raptor species have a relatively low exposure to common avian pathogens and this could contribute to their success in these modified habitats. Given this dataset is now more than two decades old, we recommend follow-up studies to re-evaluate the health status of these and other raptor species currently inhabiting the Pampas agroecosystems of central Argentina.