Marian’s Wildlife Blog for March 2018

Blue Jay perching by Doug Pederson

Who’s top bird at your feeder? An interesting thing to observe while you are identifying birds is who is displacing whom at the bird feeder. This displacement behavior in birds is called a “dominance hierarchy”. For instance, we think of doves as peaceful and jays as aggressive. Cornell Lab of Ornithology set out to study displacement behavior at feeders, to see who comes out on top in bird interactions. Project Feeder Watch participants have been gathering the displacement data.

Eliot Miller at Cornell Lab correlated 7,685 observations sent in by Feeder Watchers. In general, he found what one would expect, bigger is better. Blue Jays displace mourning doves and downy woodpeckers displace tufted titmice. But there were also some surprises.

The Project Feeder Watch Blog of October 9, 2017 reports on Miller’s study of 136 species of birds observed interacting at Feeder Watch sites in North America. Miller ranked each species based on how often it displaced other species, and how often it got displaced. Then he arranged all those species in their order of dominance. The highest- ranking species, the toughest bird, was the Wild Turkey. At the bottom of the list was the Eurasian Tree Sparrow. Eurasian Tree Sparrows, an introduced species which lives in parts of the mid-west, is closely related to our much more aggressive House Sparrows.  read more…