1Present address: D. E. Chamberlain, Department of Animal Biology, University of Turin, via Accademia Albertina 17, 10123 Turin, Italy.
What makes an urban bird?
Article first published online: 13 MAY 2010
© 2010 Blackwell Publishing Ltd
Global Change Biology
Volume 17, Issue 1, pages 32–44, January 2011
How to Cite
EVANS, K. L., CHAMBERLAIN, D. E., HATCHWELL, B. J., GREGORY, R. D. and GASTON, K. J. (2011), What makes an urban bird?. Global Change Biology, 17: 32–44. doi: 10.1111/j.1365-2486.2010.02247.x
- Issue published online: 1 DEC 2010
- Article first published online: 13 MAY 2010
- Received 7 January 2010; revised version received 19 March 2010 and accepted 26 March 2010
- brain size;
- niche position;
- species traits;
- urbanization index
Urban development is increasing across the globe. This poses a major threat to biodiversity, which is often relatively poor in towns and cities. Despite much interest in identifying species' traits that can predict their responses to environmental degradation this approach has seldom been used to assess which species are particularly vulnerable to urban development. Here we explore this issue, exploiting one of the best available datasets on species' responses to towns and cities in a highly urbanized region, comprising avian densities across approximately 3000 British urban and rural 1 km × 1 km grid cells. We find that the manner in which species' responses to urbanization is measured has a marked influence on the nature of associations between these responses and species' ecological and life history traits. We advocate that future studies should use continuous indices of responses that take relative urban and rural densities into account, rather than using urban densities in isolation, or a binary response recording the presence/absence of a species in towns and cities. Contrary to previous studies we find that urban development does not select against avian long-distance migrants and insectivores, or species with limited annual fecundity and dispersal capacity. There was no evidence that behavioural flexibility, as measured by relative brain size, influenced species' responses to urban environments. In Britain, generalist species, as measured by niche position rather than breadth, are favoured by urban development as are, albeit to a lesser extent, those that feed on plant material and nest above the ground. Our results suggest that avian biodiversity in towns and cities in urbanizing regions will be promoted by providing additional resources that are currently scarce in urban areas, and developing suitable environments for ground-nesting species.