Physical Geography and Sciences


Connor McGrath



Download Full Text (2.3 MB)


Connor McGrath, Biology
Faculty Mentor: Professor Gavin Leighton, Biology

The evolution of both diverse and similar phenotypes has long been a goal in evolutionary biology. Recent research in evolutionary biology has identified the presence of pairs or groups of mimicry among woodpeckers. This project was conducted to investigate whether Downy woodpeckers evolved a similar appearance to the more dominant Hairy woodpecker in order to trick third-party species into relinquishing resources. This was studied by recording the reactions of local birds to models of each species placed at feeders. We discovered that, while responses to the two model types were far from identical, birds avoided feeders with attached models more than unmodified feeders in both cases. However, interaction rates between individual species of birds at the feeder hinted that there may be some birds which are more dominant than Downy woodpeckers but less dominant than Hairy woodpeckers, leading them to disregard only the Downy model. The effects of this instance of mimicry seem to be more complicated when dealing with the reaction of multiple species, it is possible that only certain third-party bird species are targeted, while others judge dominance based on size as well as pattern. These would be more inclined to avoid Hairy woodpeckers, while remaining comfortable around Downy woodpeckers. Overall, Downy woodpeckers appear to accrue at least some of the benefits of dominant Hairy woodpeckers based on their appearance. This study adds more support to the hypothesis that several third-party native birds, not Hairy woodpeckers themselves, are the main target of Downy woodpecker mimicry.

Publication Date


The Evolution of Mimicry in Hairy and Downy Woodpeckers
Off-campus Download