Anyone who has moved from the country to a big city will know how vital it is to get “street smart” as quickly as possible in order to survive, but it appears that humans aren’t the only animals that undergo cognitive transformations when adapting to urbanization. According to a new study by researchers from McGill University, Montreal, birds living in cities may have superior problem-solving and learning skills than their rural counterparts.
The paper, which appears in the journal Behavioural Ecology, explores the hypothesis that city birds are likely to develop certain cognitive capabilities in order to help them compete for resources in urban settings. Acclimatization to such environments should also lead to increased “boldness” and decreased “neophobia,” meaning urban birds should be less spooked by the presence of humans or unfamiliar items than rural birds.
Because a great deal of energy is required in order to develop these cognitive traits, the researchers expected to find that city-dwelling birds would have inferior immunity to that of country birds, as less biological resources are available for the development of antibodies.
To test these hypotheses, the study authors set up a range of experiments using bullfinches captured from both urban and rural environments in Barbados.
As expected, those collected from cities were more innovative and faster learners when required to pull on strings and open lids in order to access food, suggesting an enhanced problem-solving ability. These birds were also “bolder” than those found in rural environments, indicated by their willingness to approach food despite the nearby presence of humans.
Interestingly, however, urban birds were actually found to be more neophobic than rural birds – a characteristic which the researchers measured by observing how likely they were to be put off from feeding when strange items were placed near the food source. Unable to explain exactly why this is the case, the study authors conclude that the increased mental flexibility of city birds is in no way connected to decreased neophobia or a willingness to explore unfamiliar elements, as had initially been predicted.
To test for immunocompetence, the researchers injected the birds with a compound called phytohemagglutinin before measuring the extent of the swelling this provoked, as this provides a measure of the strength of the immune response. Contrary to their hypothesis, the authors found that urban birds actually had superior immunocompetence to rural birds, and suggest that this may be caused by exposure to a wider diversity of pathogens in cities.
Commenting on these findings, lead researcher Jean-Nicolas Audet remarked that “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… [However] it seems that in this case, the urban birds have it all.”
