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.