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Commentary
Nobody Told the Birds About Global Warming
By Harold Brown
If your mind is made up about global warming, all confirmation is welcome, no matter how flimsy or suspect. Even the free movement of birds is used to confirm warming and alarm our citizens.
The National Wildlife Federation states on its Web site, “The Brown Thrasher is in danger of disappearing from Georgia.” In a global-warming editorial, one newspaper noted the thrasher is returning from winter migration 21 days earlier than it did 20 years ago.
Bullfeathers! Humans have very sensitive instruments for measuring temperature and still are uncertain of global warming; how does our state bird know?
In contrast to this suspicious behavior of the brown thrasher, other species have been nesting progressively farther south for more than half a century; not as if our climate is becoming warmer, but as if it is cooling. Nobody but a few serious birdwatchers seems to have noticed. World-famous ecologist Eugene Odum and co-workers noted the invasion of 14 species into the Athens area in the 20th century, mostly from the north.
The American robin is familiar to Georgians and perhaps we think of it as being everywhere, not shifting in its habits. But it underwent radical change in the 20th century, building its nests farther south. In 1946 Odum noted, “Until only a very few years ago it nested only in the extreme northern part of the state, but now has spread almost the length of the state.”
Confirmation comes from the annual North American Breeding Bird Survey, conducted every year across the country by the U.S. Geological Survey. In Pike County near Griffin, the survey has found an average of 21 robins per year since 1994, one third more than the count of brown thrashers. During those years, two robins per year were counted in Wrightsville, well into the Coastal Plain. So, although robins have always migrated north across Middle Georgia in late winter, in recent decades they have been nesting there during summer, and even farther south. In August, I saw robins in Statesboro, where my brother said they nested in his yard.
The song sparrow in Georgia is spreading southward, too: In 1946, Odum and Burleigh described a line from Ellijay to Cleveland to Lakemont in extreme Northeast Georgia that “approximately represents the present ‘front’” for the bird. Today, the Breeding Bird Survey regularly finds the song sparrow near Cartersville (Bartow County; two per year since 1980), Bowdon (Carroll County; none before 1993; almost two per year since then), and Siloam (Greene County; none before 1982, but 3.9 per year since).
Odum also listed the barn swallow in 1946 as a species “which may be pushing south.” The swallow was observed in the first survey, in 1967, at Baldwin in Habersham County. It was first observed in counts at Athens in 1975; in Monroe County above Macon in 1973; Pulaski County south of Macon in 1976, and near Baxley in southeast Georgia in 1983. Since 1994, twice as many barn swallows (13 in the survey) as brown thrashers nested near Baxley. In 1991, it was first observed nesting in Lanier County near the Florida line.
The southward march apparently continues. As recently as 1997, The Oriole, Georgia’s ornithological journal, reported seven “northern forest birds” (in addition to birds named above) were suspected of extending their breeding ranges farther south in the northeast corner of Georgia.
The next time someone declares global warming is disrupting ecological habitats, remember the dozens of birds spreading their nests southward across Georgia. Perhaps they are responding to southern cooling, because the South has, in fact, cooled. Not, of course, in cities like Atlanta, which developed “heat islands,” but in smaller places representing the countryside.
Most records for such places in Georgia show a cooling in the 20th century. A graph for Newnan, from the Web site of the Center for the Study of Carbon Dioxide and Global Change, shows that temperatures there have cooled 2.5 degrees to 3 degrees since the 1920s.
It’s hardly likely that the brown thrasher and the other birds are responding to global warming. Professor Odum and his colleagues didn’t believe so, either, concluding in 1993: “It would seem that so far in the 20th century there have been no consistent temperature changes that would favor either northward or southward range extensions.”
The brown thrashers are unlikely pawns in the global warming struggle. Our state fowl has no thermometer and doesn’t read the popular press. How can they suspect the world is warming?
It would pain me to think that the bird we have elected to represent our state is dumb enough to hurry North earlier each spring because it supposes the world is getting warmer, when another splendid flock is headed South. I would lead a campaign to vote ’em out and elect the chicken: It has stayed put for 200 years, and whoever heard of southern fried brown thrasher?
Some “thrashers” in this scuffle over global warming need a reality check, and it ain’t the birds.
University of Georgia Professor Emeritus Harold Brown is an Adjunct Scholar with the Georgia Public Policy Foundation and author of “The Greening of Georgia: The Improvement of the Environment in the Twentieth Century.” The Georgia Public Policy Foundation is an independent think tank that proposes practical, market-oriented approaches to public policy to improve the lives of Georgians. Nothing written here is to be construed as necessarily reflecting the views of the Georgia Public Policy Foundation or as an attempt to aid or hinder the passage of any bill before the U.S. Congress or the Georgia Legislature.
© Georgia Public Policy Foundation (September 24, 2004). Permission to reprint in whole or in part is hereby granted, provided the author and his affiliations are cited.
