How Stressed are Birds in an Urbanizing Landscape? Relationships Between the Physiology of Birds and Three Levels of Habitat Alteration

[摘要] Abstract. In this study we measured two physiological traits (levels of corticosterone and immunoglobulin) in two species of landbirds, the Canyon Towhee (Melozone fusca) and Inca Dove (Columbina inca), occupying three degrees of human alteration of a subtropical mountain landscape: forest edges, croplands, and urban sites. We found that both physiological variables differed by species and habitat condition. In both species, corticosterone concentration was significantly higher in croplands. But immunoglobulin concentration behaved differently, in C. inca being highest at urban sites, where in M. fusca it was lowest. Contrary to expectation, we only found one strong significant relationship between both physiological variables: M. fusca in urban areas. Our results suggest that 30% of the towhees captured in urban areas are under chronic stress. Results for body condition support this hypothesis, as the condition of towhees in urban areas was poorer, suggesting physiological vulnerability. Although we expe...

[学科分类] 动物科学

[关键词] corticosterone;immunoglobulin;ecophysiology;Canyon Towhee;Inca Dove;urban—agricultural matrixes;forest edges