The Earth is undergoing a period of rapid climate change that is enhanced by atmospheric carbon enrichment from human activity over the past 100 years. All organisms depend on their habitats for food, water, shelter, and opportunities to breed and raise young. Climate changes can affect organisms and their habitats in many ways. In fact, climate change likely impacts all life on Earth, from individual organisms to populations, species, communities, and ecosystems. It may alter behavior, population size, species distributions, plant and animal communities, and ecosystem function and stability. How strongly different species will be affected differs, depending on differences in their ecology and life history. Species with small population sizes, restricted ranges, specialized habitat requirements and limited ability to move to different habitat will be most at risk. Similarly, different habitats and ecosystems will be impacted differently, with those in coastal, high-latitude, and high-altitude regions most vulnerable.

Likely Changes

During the last 2 billion years, the Earth has gone through several extended periods of cooling and warming, which have resulted in dramatic changes in vegetation and species composition (Graham and Grimm 1990, MacDonald et al. 2008). Effects of the current trend in global climate change include extensive warming, changing patterns of precipitation, changes in season lengths, declining snowpack, and increasing frequency of severe weather events.

How might these changes affect birds? Here is an example: using the National Audubon Society’s Christmas Bird Count data, Price and Root (2001) have shown that, in North America, the northern limits of many bird species are strongly associated with various climatic variables (e.g., winter temperature). Further analyses revealed that both the ranges and the abundances of birds shift, on an annual basis, in concert with temperature. Indeed, studies have shown that a significant number of migrating birds are arriving up to 3 weeks earlier now than they did in 1960. Apparently, many bird species can and do respond to changing climatic conditions. Because their ranges are limited by vegetation, however, these birds will probably not be able to shift their ranges with the changing climate— at least not until the vegetation itself shifts. Consequently, natural communities of birds may change dramatically in the future as changes in climate and vegetation favor some species and harm others. It is difficult to predict how these changes will influence community structure or function.

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, and the number and proportion of residents and short-distance migrants increased. In North America, many songbirds are long-distance migrants. Species such as Baltimore oriole (Icterus galbula), barn swallow (Hirundo rustica), wood thrush (Hylocichla mustelina), and scarlet tanager (Piranga olivacea) could well be driven from the places where we expect to find them, and more ominously, from the habitats to which they are best suited.
A 90-percent decline in sooty shearwaters (Puffinus griseus) off the California coast in just 7 years (1987-1994) has been associated with warming of the California Current, which flows from southern British Columbia to Baja California.

Useful Links

Global warming and birds
http://www.audubon.org/globalwarming/files/GW%20and%20birds%20041707.pdf

Birds and global warming
http://www.nwf.org/birdsandglobalwarming/

Global warming will hurt migratory birds
http://news.mongabay.com/2007/0507-birds.html

The ecological effects of global warming on North American birds and butterflies
http://www.usgcrp.gov/usgcrp/seminars/961010DD.html

Global warming and boreal birds
http://www.borealbirds.org/globalwarmingbirds.shtml

References Cited

Graham, R.W.; Grimm, E.C. 1990. Effects of global climate change on the patterns of terrestrial biological communities. Trends in Ecology & Evolution 5. (9):289-292. 1990.

Price, J.T.; Root, T.L. 2001. Climate change and Neotropical migrants. Transactions of the North American Wildlife and Natural Resources Conference. 66: 371-379.

Recommended Citation

Raphael, Martin G. 2008. Effects of global climate change on birds. (October 28, 2008). U.S. Department of Agriculture, Forest Service, Climate Change Resource Center. http://www.fs.fed.us/ccrc/topics/birds.shtml.

Effects of global climate change on birds

Issue

Likely Changes

Recommended Reading

Useful Links

References Cited

Recommended Citation