Birds and climate change: ecological disruption in motion

Each year for more than a century, dedicated volunteers have braved snow, wind, rain and ice to record the number and location of North American birds. The carefully organized and compiled observations of tens of thousands of Citizen Scientists participating in Audubon’s annual Christmas Bird Count have grown to form the world’s longest uninterrupted repository of bird population information. Analyses of its data have time after time revealed important trends, alerting America to perils and opportunities with implications far beyond avian well-being. Birds are well-known barometers of environmental health. Changes in their condition can warn of threats to habitats and natural systems critical to all life on earth. Like canaries in a coal mine, they can alert us to danger. And, if we heed their warnings, caring for the birds can help us protect ourselves and the future of the world we share. Amid mounting concerns over accelerating global climate change, Audubon looked to the birds to determine if and how these sensitive creatures might be responding to changes here in the continental U.S. Birders have long reported surprising sightings of species far north of expected ranges. But are the reports significant? If so, are they connected to documented changes in our climate? Analyses of four decades of Christmas Bird Count data provide some answers. The results confirm what bird lovers have long suspected. Findings summarized in the pages that follow offer a look at forty years of change, a peek at what the future likely holds in one part of our nation, and an urgent message of warning from the birds—a message we would be wise to heed.