Birds and Climate Change

The 112th Christmas Bird Count was held in New York City this past weekend.  This annual survey gives scientists a picture of how the avian population is changing in a given area. The analysis of recent CBC studies by the Audubon Society shows that climate change is having a serious impact on the songbird population in North America.

Migration is a regular seasonal event for many species of birds.  In general, they fly north in the spring to breed and south in the autumn to find food.  The changing amount of available daylight in the sky signals the birds to begin their great treks. Their food sources such as insects, on the other hand, are mostly driven by temperature.  As global temperatures rise, spring warmth is arriving earlier and unbalancing the migration cycle.  This means that by the time migratory birds arrive at their northern breeding grounds, they will have missed the peak bug season. This in turn, affects the birds’ ability to feed their young and therefore the overall population count.

Studies are showing that some species of birds are adapting to the changing climate by shifting their winter ranges northward. Those who have not been able to adapt are predicted to go extinct as global temperatures continue to rise.  Birds that do not migrate may see an increase in number as winters grow shorter and food sources are renewing themselves earlier.  In any case, the variety of songbirds we see at our backyard feeders throughout the winter will be changing.

Major Migratory Bird Flyways in North America

Image Credit: U.S. Fish and Wildlife Service