Urban habitats are challenging, with wildlife constantly adapting to complex and changeable environments. These urban environments are relatively new in terms of animals’ evolutionary history, so it has been predicted that animals living in these urban areas are likely to be bolder, better at learning and problem solving, and less likely to be fazed by new situations.
Biologists from McGill University in Montreal, Canada, tested this hypothesis, using the Barbados bullfinch Loxigilla barbadensis. 53 bullfinches were caught from a number of urban and rural locations in Barbados and kept in captivity for 3 days before the study began.
As a measure of boldness, the finches were first presented with seeds to see how quickly they would approach and eat them. A novel object was then placed alongside an identical dish of seeds to assess how they responded to unfamiliar situations and stimuli.
To check their problem-solving skills, birds had to gain access to food through different tricky containers. The faster they got to the food, the better their problem-solving abilities were ranked.
Watch the birds solve problems to access their rewards in the video.
The predictions held true in some areas, but not in others. The researchers found that city birds were indeed better at problem-solving than country birds, and were naturally bolder. However, no difference was found between learning abilities, and city birds were interestingly more afraid of unknown situations than their country counterparts. Urban birds also had better immune systems, perhaps due to a higher risk of disease in city environments.
It is no surprise that the urban bullfinches were better problem solvers, as this would allow them to adapt to a city environment, exploiting the more limited and varying resources found in these habitats. However, the fact that the urban birds had stronger immune systems did come as a surprise to the researchers.
“We found that not only were birds from urbanized areas better at innovative problem-solving tasks than bullfinches from rural environments, but that surprisingly urban birds also had a better immunity than rural birds,” explains Jean-Nicolas Audet, the lead author of the study. “Since urban birds were better at problem-solving, we expected that there would be a trade-off and that the immunity would be lower, just because we assumed that you can’t be good at everything’ (in fact, both traits are costly). It seems that in this case, the urban birds have it all”.
“The town bird and the country bird: problem solving and immunocompetence vary with urbanization” Jean-Nicolas Audet, Simon Ducatez and Louis Lefebvre, Behavioral Ecology, http://doi.org/10.1093/beheco/arv201
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