ATHENS, Ga. -- A small gentle shorebird, hunted nearly to extinction earlier this century as an adornment for women's hats, is perched on the brink again. Crowded off its natural beachfront nesting grounds by frisbee-throwing vacationers and high-rise hotels, the beleaguered Atlantic least tern has resorted to nesting on roof-tops.
A new study by University of Georgia wildlife researchers has found that nearly all of Georgia's 1,200 to 1,500 surviving least tern pairs are nesting on some type of artificial site, whether it's roof-tops or man-made sand hills called "spoils," dredged from ocean channels. Another 125 or so pairs still try to nest on beaches each year without much success. The researchers say without further protection, the Atlantic least tern, already listed as "rare" by the Georgia Department of Natural Resources, is vulnerable to further decline.
"Successful breeding depends on having large, intact colonies," said Dr. Sara Schweitzer, a wildlife ecologist in UGA's Warnell School of Forest Resources. "The few remaining beach colonies have the absolute last tatters of usable beach, and they're being flooded out. So these artificial nesting sites are crucial."
The research, which was presented last year at national meetings of the Colonial Waterbird Society, the Association of Field Ornithologists and The Wildlife Society, was supported by grants from the Georgia Department of Natural Resources Wildlife Resources Division, the Max McGraw Wildlife Foundation and the UGA Research Foundation.
About the size and color of a mockingbird, the Atlantic least terns fly over shallow water, hunting for minnows and other small fish. Their aerial acrobatics delighted nineteenth century beach goers who nicknamed them "sea swallows." They once nested up and down the East Coast, but their long, fancy black and white wing and tail feathers made them a fashion target. From the 1870s to the early 1900s, they were slaughtered by the hundreds of thousands.
Most were shot at close range while they hovered protectively above their nests. Resident fishermen and oystermen got 10 cents a piece for the birds, which they gutted and shipped in ice to supply New York's millinery trade. The birds made a brief comeback in the 1920s and ?30s, but by the early 1940s coastal development caused their numbers to dive again.
Though already listed as "rare," meaning monitored but not protected, the Atlantic least tern has faired slightly better than its cousins, the interior and the California least terns. Both are threatened due to habitat loss.
Schweitzer and graduate student Michael Krogh, who monitored the Atlantic least terns in 1995, ?96 and ?97, are encouraged by the reproductive success of the roof-top colonies. Seventy-two chicks in 1996 and 114 in 1997 fledged from roof-tops, the large majority from just three large colonies that nested on three Savannah-based manufacturing plants. Not a single chick fledged from the small, scattered beach colonies.
But researchers worry that a hurricane or other single catastrophic weather event could wipe out Georgia's entire roof-top population. Another concern is that few firms still build the type of flat, graveled roof-tops that mimic the isolated beaches the privacy-prone terns require for nesting.
"A lot of people who love the beach just don't realize what's happening," said Schweitzer. "The colonies on sand spoils need to be fenced off to protect the nests from humans as well as domestic pets, which are a real problem. And roof-top colonies could use help, too."
Roof-tops offer the terns a haven from people and pets. But bad weather, flooding and high roof-top temperatures that can reach more than 150 degrees take a gruesome toll on reproductive success. Krogh found many chicks and eggs baked in the afternoon sun. Others tumbled off the roofs' edge.
The scientists say coastal building codes should encourage gravel roofs with parapets, or edging at least three, and preferably 12 inches high, as well as screened drains and rain spouts that prevent chicks and eggs from washing down with the water.
Least terns are also nesting on roof-tops off the Carolinas and Florida, but it seems to be a southern trend. Schweitzer recently read about least terns in Maryland using roof-tops but isn't aware of colonies further north that have adopted this lofty survival strategy. And, at this point, roof-tops are a crucial safety net for the species. A study in Florida showed the terns didn't return to sites where graveled roofs had been replaced with vinyl or other materials.
"There's a lot we can do to help the least terns," said Schweitzer, "and they're such amazing little birds, it would be a tremendous loss to let them slip away." -30-
WRITER: Helen Fosgate,
706/542-2079,
hfosgate@smokey.forestry.uga.edu
CONTACT: Sara Schweitzer,
706/542-1150,
schweitzer@smokey.forestry.uga.edu