Three state-endangered bird species — the Forster's tern, the common tern, and the osprey — have headed to warmer climes after a successful breeding season in Chicago Wilderness. With any luck, these reestablished populations — the only successful nests in the state — may prove a foothold for nesting bird recovery in Illinois.

Forster's Last Stand — Again
The Forster's tern, Sterna forsteri, received the most spectacular welcome-home present of the three returning bird species: a custom-built island. With much of the bird's open-wetland habitat in the state now degraded by development, the Forster's tern had taken its last breeding stand in Illinois on a low-slung, wet island in Grass Lake, in Chain O' Lakes State Park. But wake from heavy motorboat traffic in this popular recreational area, combined with unstable water levels, gradually destabilized shoreline vegetation. In just 30 years, the terns' island had washed away to almost nothing, forcing the colony to abandon its nests to the waves in 1996.

But the Fox Waterway Agency (FWA), in collaboration with the Illinois Department of Natural Resources (DNR) and the Army Corps of Engineers, has been slowly rebuilding the island. The agency has pumped tons of sediment — dredged to keep boating channels in the lake open — into large "geotubes" made of synthetic fabric. These geo-tubes surround the submerged ghost of the muddy island and protect it from further erosion. Since last summer, pumps have been spewing dredged mud into the center of the ring of geotubes.

A Forster's tern brings home a fish dinner. The common tern closely resembles the Forster's but is typically more aggressive. Photo by Chris Young/State Journal-Register.

DNR biologist Brad Semel and Illinois Natural History Survey Graduate Research Assistant Mike Ward recognized the island's habitat potential early on. They began talking with the FWA, which soon had rebuilt enough of the island's land area for Semel to install a small mat of dead cattails and bluejoint grass, the material upon which the terns' prefer to nest.

Last April, as migrating terns had begun to pass through the area, Semel and Ward set up a solar-powered CD player issuing round-the-clock mating calls. Two weeks later, they added 26 brightly painted decoys. Within two days of placing the decoys, Forster's terns had begun to build nests and lay eggs. As of early July, more than 120 adult Forster's terns had raised at least 120 fledglings. "It was amazing," says Ward. "With conservation, you usually have to be patient. This happened so quickly, with such good success."

Not-So-Common Tern
Roughly 20 miles to the east of the Chain O' Lakes, on the shore of Lake Michigan at Great Lakes Naval Training Center, a tenacious colony of common terns, Sterna hirundo, recently raised about 40 fledglings. The nearly 50 adult terns here dive-bomb, scream at, and occasionally draw blood from the helmeted biologists who regularly survey the colony, but the terns have themselves been chased from home after lakefront home by human disturbance, development, and predators.

Common tern eggs and chicks are vulnerable to predators, human footsteps, and
overheating. Photo by Chris Young/State Journal-Register.

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Before conservationist Donnie Dann and the DNR's Semel started this project, common terns hadn't fledged any confirmed young in Illinois since 1983. The terns started colonies year after year at what is now the nearby Midwest Generation power plant, only to be preyed on by raccoons, rats, coyote, and a peregrine falcon.

Then, in 1999, Dann discovered common tern eggshells on a small island downshore of the plant, just off the end of a peninsula by the Navy's small harbor. The island was overgrown with invasive plants and occasionally tromped by the splashing boots of Navy recruits. But Dann and Semel secured cooperation from the Navy, recruited volunteers to cut back the invasives, and installed a fence to deter predators and other invaders. These actions eventually led to the first successful nesting season in 2002.

This June, however, a coyote jumped the fence, devouring the contents of the colony's 26 new nests. Conservationists electrified the fence. The adult terns laid new eggs, and as of early August this year, 34 common tern chicks fledged — which, to non-ornithologists, means they survived long enough to enjoy the relative security of flight.

Osprey Young Grow Up So Fast
Conservationists celebrated this April when bird monitors Craig Thayer and Wes Serafin reported a pair of nesting osprey, Pandion haliaetus, atop a nesting platform at one of Cook County's Palos Division forest preserves. The osprey pair successfully fledged two young this year. Habitat loss and DDT have driven these majestic fishing raptors from much of the Midwest, but the osprey gained a foothold at this site when three fledglings finally peered over the edge of their treetop nest five years ago, marking the species' first breeding success in Illinois in at least a half-century.

	An osprey family made a home this summer atop this nesting platform, beside a slough in the Palos region. Photo by Mike MacDonald, www.ChicagoNature.com.

Following that first successful year, birders recommended that the Forest Preserve District raise the current nesting platform, now one of six in Chicago Wilderness. Common-wealth Edison donated the telephone pole for the platform. The osprey took to the nest only days after the district installed it. They raised young there for another two years, but failed in 2001 and 2002, making this year's success even more important.

Osprey have silently returned to other places in Chicago Wilderness, too, a phenomenon biologists largely attribute to declining levels of DDT in the environment. In April, birders reported the arrival of a pair in the Calumet region of Chicago, though these haven't yet raised young. "It's typical for first-time nesters to fail nesting," says Serafin. DNR biologist Dan Kirk has also spotted a new pair of osprey with one juvenile along the Fox River in Kendall County.

Challenges Ahead
The outlook for these new nesting outposts remains precarious, but hopeful. Proposed construction near the Palos nest site may be too much for the osprey. And in late July, Semel approached the Forster's tern colony and immediately noticed that the birds were gone. On July 17th, he learned, a drunken boater had crashed a craft into the geotube only 240 feet from the colony, attracting scores of rescue vehicles and killing some terns. At around that same time, the Fox Waterway Agency had also begun to dump dredged mud only 40 feet from the colony.

The knowledge that some of the birds, both young and adult, had already begun to migrate gives Semel some comfort. "It was still a successful year," he says, "but a real eyeopener." It showed that many species increasingly need the dedication and creativity of these wildlife protectors and countless others in Chicago Wilderness.