Even when bird feeders are readily available, some species of birds head for warmer climes, says a paper in the latest issue of the Journal of Animal Ecology. The scientists, who are affiliated with the Cornell Lab of Ornithology’s Project FeederWatch, studied 18 bird species that are common at bird feeders in the northeastern US and found that some species of birds did not stick around over the winter in spite of there being plenty to eat at bird feeders.

They also found that the birds that stayed north in winter were more likely to visit a bird feeder during a cold snap. Finally, the scientists found that for species that tolerate urban life, such as house sparrows, the abundant bird feeders in developed areas provide a winter refuge. Species that find urban life stressful, such as downy woodpeckers, are less likely to stay in developed areas during winter.

The scientists note that when predicting how climate change will influence a bird species, these other factors, such as tolerance to urbanization, need to be considered as well.

You can find the paper here, and a simple summary of the work on the Project FeederWatch blog.

Photo: I say it’s a nuthatch, although admittedly not the nuthatch species in this study. So don’t look too closely at the bird, just look at the bird feeder and the pretty green background, OK?