Leukocyte profiles and body condition of free-living Burrowing Owls (Athene cunicularia) from rural and urban areas in the Argentina Pampas

Abstract

Animals living in urban areas are exposed to novel and potentially stressful human disturbances. In response to the increased number of stressors in these habitats, they may manifest changes in their immune system, body condition and physiology. Many bird species are negatively impacted by urbanization, whilst other species thrive in urban areas. The capacity to adjust the physiological responses to the stressors associated with urban areas may play a key role in explaining the success of some bird species in these environments. In his study, we compared indicators of physiological stress response and body condition in freeliving Burrowing Owls (Athene cunicularia) inhabiting urban and rural areas. We calculated a scaled index of body condition, and assessed leukocyte profiles and the heterophil/lymphocyte ratios of chicks and adults. We found no significant differences in these parameters between individuals from rural and urban areas. Chicks showed higher relative leukocyte counts than adults, which may be associated with ontogenetic development and immune system activation processes.