Unusual Habitats

These rare birds flock to a shopping mall in search of home furnishings

06-01-1999 // Howard Youth

Atlantic Coast least terns shopping for safe nesting grounds are finding a good deal at Glynn Place Mall in Brunswick, Georgia. A flock of about 200 terns has recently been nesting on the mall´s gravel and tar roof, one of a growing number of roofs hosting colonies of these rare birds.

The robin-sized terns descend on the mall each spring because their traditional nesting sites--undisturbed beaches--are now at a premium. "Least terns were once distributed across natural beaches in Georgia," says Sara Schweitzer, a biologist at the University of Georgia who monitors the state´s least tern colonies. "But those locations are also desirable to people and development."

While nesting on high has drawbacks, in many built-up areas it is now the best the birds can do. Seventy-three percent of Georgia´s 1,270 known breeding least tern pairs nested on gravel rooftops, compared with only 1 percent on beaches, according to a 1997 study by Schweitzer and her colleague Michael G. Krogh. The remaining 26 percent settled on dredge-spoil islands, where sand has been dragged up and dumped to clear channels. Of all the sites, the Glynn Place Mall had the highest nesting success, with 53 percent of the eggs hatching.

The rooftop nesting trend represents some good news for the beleaguered least terns. Once abundant along sandy beaches from the East Coast to Southern California, these dainty water birds became scarce after receiving a one-two punch from unregulated hunting, then habitat loss.

Rooftop nesting colonies have turned up since the 1970s in Georgia, Maryland, North Carolina, South Carolina, Florida, Alabama, Mississippi, Louisiana and Texas, providing hope that the least tern might once again bounce back. Of the tern´s three subspecies, only the widespread Atlantic Coast population, which numbers more than 40,000 birds nesting from Maine to Texas, has been recorded nesting on roofs. The other two subspecies are federally listed as endangered. The interior least tern, which nests on river sand bars from the Mississippi Delta north to South Dakota, numbers about 6,800 birds. The California least tern population, which hangs on in coastal Southern California, totals more than 8,000.

Since 1995, least terns have appeared at Glynn Place Mall in late April, after spending the winter fishing in tropical waters as far south as northern South America. Soon after arrival, the birds scrape out nests, in which the females lay one, two or (rarely) three, gray, brown-dappled eggs. Males and females share incubation duties for about three weeks until the eggs hatch. After a few days, hatchlings scramble away from the sunny nests, seeking the shade of the parapet and air conditioning units. (On beaches, the young scramble for the shade of dune grasses.) Despite the shuffling of nestlings, adult terns somehow sort out their own young after returning from feeding sorties in nearby ponds or at the beach, which lies one-and-a-half miles to the east. By mid- to late July, the young fly off, usually sticking close to their parents for a month or more.

While the terns grow and fledge on the roof, shoppers inside the mall mill about in air-conditioned comfort. "If it´s helping the terns to nest, I think it´s fine," says Carmelita Culpepper, a Brunswick shopper who had read about the mall´s nesting least terns in the local newspaper. Dennis Booher, a mall security guard, confesses, "At first I thought they were intruders. They can make a lot of noise on the roof."

Perhaps the terns´ greatest champion is Everett Clark, the Glynn Place operations manager. Clark has worked closely with wildlife officials to protect the rooftop colony since local birders and biologists first reported seeing least terns near the mall in 1995. "We control who goes on the roof," he says. "Some technicians snicker, but a lot of them care about the birds."

As roofs go, the one on Glynn Place Mall is almost ideal. A three-foot-tall parapet fringes the entire roof, keeping the young from toppling to their deaths and providing them with shade. Mesh covers cap drains and rain spouts, and the sweating air conditioners both shade and dampen birds that stand beneath them. Despite all these features, many eggs do not hatch, and nestlings die. Some succumb to exposure and dehydration--the mall´s rooftop temperature can reach 150 degrees Fahrenheit, even hotter than a sun-seared beach. Some eggs are also crushed when adults take off from the nest and mash eggs into the gravel, which is much less forgiving than soft beach sand.

While more than half of the Glynn Place Mall´s tern eggs hatched in the 1997 study, none successfully hatched from the natural beach nest sites. At beaches, floods and high tides washed out some colonies, while people disturbed nests and young at others. Predators, including raccoons, dogs, cats and coyotes, plagued terns at dredge-spoil sites.

Despite the seemingly good news about gravel rooftops and Georgia´s least terns, the birds´ future still worries conservationists. For one thing, gravel and tar rooftops are becoming less popular with roofers, who now favor a rolled rubber substitute that does not attract terns. Schweitzer and her colleagues promote the use of gravel and tar roofing materials. They also propose better management of other nesting sites, including periodically clearing weeds to maintain the beachlike quality of dredge-spoil sites, fencing off beach and dredge-spoil colonies, and more vigilantly guarding wild beach sites during nesting season.

Schweitzer wonders what the future holds for Georgia´s rooftop terns. "They might come back for years and years," she says, "but with increased development and changes in rooftops, we don´t know for sure what´s going to happen."

Maryland writer Howard Youth says his encounter with the Glynn Place terns was one of his best mall visits ever.

Join today and get a 1 year subscription to National Wildlife magazine
     Flickr Icon           Find NWF on Facebook.           Follow NWF on Twitter.           YouTube Icon    
Connecting...
Certify your yard today!