Urban and rural birds: genetic differentiation and the process of urbanisation.

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Urban areas are often regarded as being of little importance for biodiversity, conservation effort instead being directed at rural habitats. However, urban habitats are occupied by many species, some of which live at higher density than in their traditional rural habitat. Despite the potential importance of the urban environment for wildlife, our knowledge of urban ecology is surprisingly poor; furthermore, we know little of the process through which a species makes the transition from being a rural species to an urban one. The aim of this project is to investigate how a typical urban bird, the blackbird, has become such a familiar species in towns and cities across much of Europe. The first objective will be to use historical records to trace in detail the blackbird's colonisation of urban areas across Europe since the earliest records in Germany in 1820 to the present day, when cities in NE and E Europe are still in the process of being colonised. The second objective is to obtain DNA samples from blackbirds in paired urban and rural samples along a transect from the earliest areas of colonisation to areas where urban occupation is currently occurring; we will then test alternative theories for the process of urbanisation by measuring the genetic similarity of blackbird populations in urban and rural habitats. Results of these analyses will enable us to determine whether urban blackbirds: (i) are simply rural blackbirds that have learnt to exploit the urban environment, (ii) have multiple origins, having adapted to the urban habitat from local rural populations, (iii) have a single origin, with subsequent spread into other urban areas by the dispersal of urban-adapted blackbirds from one city to another across Europe. The third objective is to investigate whether urban blackbirds differ from rural ones in either their morphology, their diet or their burdens of ticks, lice and blood parasites. Differences between urban and rural populations will be assessed in order to determine whether the selective pressures operating on blackbirds differ consistently between habitats.