The purple finch's wintering grounds are 433 miles farther north than 40 years ago. Photo by Ashok Khosla.
An Audubon Society study released today shows a startling link between climate change and bird ranges. Nearly 60 percent of 305 bird species in North America are spending the winter about 35 miles farther north than they did four decades ago. The purple finch has made the largest shift, 433 miles, according to the report, which draws from forty years of citizen-scientist Christmas Bird Count data.
While a variety of factors affect bird ranges—including urban sprawl and food availability—such a large shift in so many species provides powerful evidence that global warming is the main cause.
Not all species are on the move. Grassland species are largely staying put (only 38 percent are mirroring the northward trend), but that may be because there isn’t habitat available for them outside their current ranges. Many of these species, including the Eastern Meadowlark and Burrowing Owl, might not be able to adapt to the double whammy of depleted habitat and rising temperatures.
The findings indicate that it’s imperative to develop policy to curb climate change and its impacts, as well as help wildlife and ecosystems adapt to unavoidable habitat changes. To read the report and learn what you can do to help, visit birdsandclimate.org.
Finally, here’s a look at the ten bird species whose ranges have shifted the most, from the AP. Climate change probably isn’t the main reason for the movement to higher latitudes for four of the ten (Wild Turkey, Marbled Murrelet, Ring-billed Gull, and House Finch).
Rank, Species, Estimated miles moved north 1966-2005
1. Purple Finch, 433.0
2. Wild Turkey, 407.6
3. Marbled Murrelet, 361.9
4. Ring-billed Gull, 355.8
5. Red-breasted Merganser, 316.9
6. Spruce Grouse, 316.1
7. Pine Siskin, 288.2
8. Fox Sparrow, 286.8
9. Boreal Chickadee, 279.4
10. House Finch, 269.