What Are Some Specific Impacts on Birds?
Under two scenarios of global climate change, there will be major shifts in the ranges and abundances of many of the 150 common bird species in the Eastern United States over the next 100 years or so; 50-52% of species will decrease in abundance by 25% or more, while 37-40% of species will exhibit range reductions of 25% or more.
Long-distance migrants may be more vulnerable to global warming than other species. As winter temperatures increased between 1980 and 1992 at Lake Constance in Central Europe, the proportion of long-distance migrant bird species decreased while the number and proportion of residents and short-distance migrants increased. In North America, many of our favorite songbirds are long-distance migrants. Species such as Baltimore Oriole, Barn Swallow, Wood Thrush, and Scarlet Tanager could well be driven from the places where we expect to find them, more ominously, from the habitats to which they are best suited.
A 90% decline in Sooty Shearwaters (Puffinus griseus) off the California coast in just seven years (1987 -1994) has been associated with warming of the California Current, which flows from southern British Columbia to Baja California.
All of the remaining marshland in the Blackwater National Wildlife Refuge (an Important Bird Area in Maryland that provides important habitat for many birds, including Black Rail and Saltmarsh Sharp-tailed Sparrow, two of Audubon's Red WatchList species) is expected to disappear within 25 years as a result of both climate change and aquifer extraction.
Global warming and associated drought in the Prairie Potholes region (southeastern Alberta and northeastern Montana to southern Manitoba and western Minnesota) will lead to significant reductions in the populations of 14 species of migratory waterfowl; 30-50% fewer prairie ponds will hold water in spring by 2060, with an associated 40-50% decline in the numbers of ducks settling to breed in the area.
The ranges of many European and African birds are likely to shift by at least 600 miles, with a decline in species richness and reduction in average range sizes (based on simulations made for the impacts of a variety of late 21st century climate models on European and African birds).