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Birds & Climate

The abundance and movement of bird species are important indicators of climate change, and it is an alarming fact that one in eight bird species are at risk due to warming climates worldwide. Birds provide essential ecological services such as natural pest control, pollination and seed dispersal. The arrival of migratory birds to their customary breeding grounds, when disrupted, means that small predators who depend on the availability of their eggs and nestlings for food will themselves be endangered. In the United States, almost a third of bird species in the Great Lakes regions and eastern Midwest are in danger of extinction. In other areas of the world, including Europe and Australia, the situation is equally as precarious.

Audubon's Christmas Bird Count
- The Audubon Society's annual Christmas Bird Hunt began on Christmas Day, 1900, to encourage people to count birds instead of hunt them. Data collected by participants over the last century has provided invaluable information for conservation biologists and other concerned scientists and citizens to track the status and viability of bird populations in North America. The annual count informs conservationists as they implement strategies to protect birds and their habitats, and identifies environmental concerns that may also effect humans and other species. Most recently, climate change has become one of the most important issues identified by the bird hunt over the last four decades.
Spending Winter Farther North
- In February 2009, the National Audubon Society issued a report entitled "Birds and Climate Change: Ecological Disruption in Motion," which documents a dramatic northward shift in bird ranges in the United States between 1966 and 2005. Fifty-eight percent of observed species, 177 out of 305, moved an average of 35 miles northward. More than 60 species moved more than 100 miles north, including the Wild Turkey (408 miles), Purple Finch (433 miles) and the American Robin (206 miles). Birds also moved from warm coastal states to areas where winter temperatures were no longer inhospitable to their survival. Not only did the documented annual temperature increase in the United States coincide with the northward movement of the birds, but the biological needs of the birds are consistent with this widespread trend. The analysis points to "a powerful common force contributing to the movements."
Threat to Grassland Birds
- Climate change is expected to cause increasingly drier conditions in the southwestern U.S. plains and increasing moisture in the northeastern plains. Rising temperatures and changing moisture conditions are likely to disrupt insect populations, the most important food source for many migrating birds with young chicks to feed. The bird habitat in the Great Plains is one of the most threatened environments in North America and grassland birds are declining more rapidly than any other regional groups of birds on the continent.
Increasing Bird Populations in Alaska
- Participants in the annual bird count in Fairbanks, Alaska, have made an analysis of their own annual bird counts between 1966 and 2005, and have also documented trends in average December temperature, average annual temperature and snow depth. The average December temperature increased from approximately -7 degrees Fahrenheit to -3 degrees Fahrenheit and the average annual temperature increased a little more than three degrees. During the same period, the average snow depth went from approximately 16 inches to 11 inches. The abundance of bird species in the Fairbanks region showed a rising trend as birds from more southern latitudes moved north, including the Black-capped Chickadee, American Robin and many others.

Animals & Science