Stress responses of the House Sparrow (Passer domesticus) to different urban land uses

Urbanization generates human-made habitats with novel resources. Such change is not homegeneous, and includes different urban land uses characterized by specific habitat traits. In this study we explored the ecophysiologial response of an urban-exploiter species in three different urban land uses (urban, suburban, industrial). Our results show that corticosterone (obtained through fecal samples) and immunoglobulin (obtained through blood samples) concentrations did not differ significantly among the studied urban land uses. Corticosterone and immunoglobulin concentration showed both high and low values in urban and suburban areas, while industrial areas had low and high levels of corticosterone, and medium-to-low immunoglobulin concentration values. Also, we found a negative relationship between corticosterone and immunoglobulin concentrations in industrial areas. Based on corticosterone and immunoglobulin concentration thresholds established from previous studies, our results suggest that: (1) birds in the three studied urban conditions are both stressed and non-stressed: and (2) the immune system of industrial House Sparrows could not be responding successfully to pathogens. Not finding physiological relationships in urban and suburban areas underline that this species has a large capacity to respond to the different stress and immune challenges found in urban areas. However, our results suggest that the physiological condition of industrial House Sparrows could be compromised by differences in the frequency and intensity of the stressor agents faced by the birds in this land use category. (C) 2010 Elsevier B.V. All rights reserved.