Variation in baseline corticosterone levels of Tree Sparrow (Passer montanus) populations along an urban gradient in Beijing, China

Abstract

Rapid urbanization is a major anthropogenic pressure on bird species that rely on vegetation for food and shelter. Since the baseline corticosterone concentration (BCC) in some bird species has been found to increase slightly in response to environmental challenges, we hypothesized that urbanization could also induce an increase in BCC. To test this hypothesis, we compared the BCC of Tree Sparrow (Passer montanus) populations in five urban and two rural habitats and analyzed the relationship between BCC and the degree of urbanization. Here, we show that the BCCs of Tree Sparrow populations were strongly and positively correlated with the degree of urbanization of the habitat. Average BCC of Tree Sparrows from high-rise residential areas and a university campus were significantly higher than those from rural areas, suggesting that Tree Sparrows living in highly urbanized areas have greater environmental challenges than those in rural areas. However, the average BCC of birds from an urban park was not significantly different to that of birds at rural sites and also differed significantly from that of birds at two of the other urban sites. These results suggest that urbanization could pose environmental challenges for Tree Sparrows, a species that appears relatively well-adapted to human-modified environments. The marked variation in BCC between different urban sites indicates that conclusions drawn from data collected at single sites must be interpreted with caution.

Exploratory behaviour and stressor hyper-responsiveness facilitate range expansion of an introduced songbird

“…Corticosterone release was also related to the degree of urbanization close to the catching site. Urbanization affects corticosterone regulation in other species as well [34][35][36] and a damped corticosterone response in urban areas may reflect habituation to stressors such as increased noise and human disturbance. Here, we used DCORT as an index of corticosterone regulation, rather than absolute levels of the hormone to control for individual variation in corticosterone regulation mechanisms (e.g.…”

Urban Great Tits (Parus major) Show Higher Distress Calling and Pecking Rates than Rural Birds across Europe

“…However, the results are mixed. For example, some studies reveal higher corticosterone levels (avian stress hormones) in urban compared to rural bird populations (Schoech et al, 2007;Fokidis et al, 2009;Zhang et al, 2011), whereas other studies found the opposite pattern or no significant differences (Partecke et al, 2006;French et al, 2008;AbolinsAbols et al, 2016).…”

Quantitative Estimation of the Velocity of Urbanization in China Using Nighttime Luminosity Data

“…A few but notable observations commonly show geographically explicit consequences of accelerating urban growth in China's cities: for instance, spatially shrinking and fragmentizing lake wetlands within Wuhan [33], gradually disappearing mangrove swamps with the expansion of urban areas to the shoreline in Shenzhen [34], changes in nest features of Magpies along the urban-rural gradient in Hangzhou [35], human settlement density-related fluctuations in baseline hormone levels in Beijing [36], decreased macroinvertebrate richness in stream habitats in relation to urban development level in the Qiantang River [37], and altered surface albedo owing to rapid urbanization [38]. All these observed changes and shifts seem to geographically coincide well with the dispersal of urban activities.…”