Urbanization changes the landscape dramatically, leading to decreased biodiversity and increased local extinction rates in wildlife and plant populations. But some species, like the northern cardinal, have managed to colonize and even thrive in cities. What makes these species successful?
This study compares disease prevalence in cardinals across the urban gradient. Initial results show that avian malaria infection decreases as urbanization increases, which may improve survival among city birds.
In the summer of 2010, exactly why malaria infection is less common in urban cardinals will be studied. It could be due to differences in exposure or to differences in susceptibility to infection.
At study sites in the Neighborhood Nestwatch program, blood samples are collected from cardinals and the environment is sampled for the presence of mosquitoes and other vectors of malaria.
Lab work will involve looking for malarial parasites and at the immune ability of each individual's blood plasma to prevent infection. In addition, stress hormone levels are tested because stress is known to suppress the immune system. Early data suggest that urban cardinals experience less stress than their rural counterparts, but are less able to fight bacterial infection.