Bird Feeding and Irruptions of Northern Finches: Are Migrations Short-Stopped?

The provision of seed at feeders improves the survivorship of birds, facilitates range expansions, and influences habitat choice. In this paper, I examine the notion that bird feeding in northern parts of North America can short-stop the irruptive migrations of fringillids. Indirect data to support an increase in bird feeding over the past 25 years are provided. Using an area bounded by the Appalachian Mountains to the west and the Atlantic Ocean to the east, I examined band reencounter data for six fringillids and found that the study area seems to be neither a sink nor a source of irruptive birds. Using Christmas Bird Count data for the study area (1975-1994), I show that greater irruptions tend to occur earlier in the study period. However, the data show no statistically significant increase in birds wintering in northern latitudes as predicted if migrations are short-stopped. The analysis does not provide compelling evidence of a short-stopping effect.