Winter bird feeders: Get ready for a busy season

Michele Black/Cornell Lab of Ornithology

Winter bird feeders: Get ready for a busy season

Thousands of bird watchers are helping ecologists decipher changing patterns of where birds spend the winter: Increasingly, birds that fled south for the season are staying put. As temperatures have risen over the past 2 decades, the mix of bird species flocking to winter bird feeders in eastern North America is changing, according to a study published online on Thursday in Global Change Biology, which used data collected by birding enthusiasts through Project FeederWatch. Tiny birds that used to be scarce in the frosty New England weather—Carolina wrens (above), chipping sparrows, and yellow-rumped warblers—have become an increasingly common sight. Overall, the types of birds found together shifted northward by 70 kilometers each decade, according to the study. It’s possible that other changes—primarily habitat loss—might have altered bird communities as well. But scientists have observed similar results in bird communities in Europe, as well as for individual bird species in North America, persuading researchers that climate is key, said lead author Karine Princé, an ecologist at the University of Wisconsin, Madison. No word yet on whether changing bird feeder demographics might have ecological ripple effects, as newcomers compete for scarce food in winter. But, Princé says, it’s a “strong possibility.”