Barn Swallows are a graceful, long-tailed swallow, known for building nests on human structures. After migrating more than 4,500 miles from Central and South America, the swallows begin collecting mud and grass to build their cup nests. They’ll transport between 750–1450 individual mud pellets to form the base, and line the nest with grass and feathers. Understandably, reusing nests from previous breeding seasons is common, and involves replacing last year’s inner nest material (and any parasites it might be harboring), then adding new mud around the rim. Barn Swallows have likely been building nests on human structures as long as humans have been building structures.
Until recently, the Anthropocene has been kind to Barn Swallow populations; these birds now nest on five continents, including traditional wintering grounds in Argentina. These South American nesters have an opposite life cycle, nesting in the Southern Hemisphere’s summer, November to February, and heading north for their winter, April to October. As insectivores, their populations are now suffering from enormous declines in insect populations (a 2019 study found that 40% percent of the world’s insect species are in danger of extinction). This reality makes their return to Maine each spring even more special. Listen for their high-pitched, bouncy chatter over fields starting in late April.
Backyard Bird of the Month is a feature by Maine Audubon created for the Maine Home Garden News, the newsletter of the University of Maine Cooperative Extension: Garden and Yard
Photo: USFWS
