Prothonotary warblers have declined in part because they are such habitat specialists. After wintering as far south as South America, males fly north to establish territories, soon joined by females.

One of just two North American cavity-nesting warblers, the birds seek out holes in living or dead trees. These cavities must be near or above slow-moving or still water. But the birds’ pickiness “also provided an opportunity to help them,” says Jay Keck, a habitat manager for National Wildlife Federation affiliate South Carolina Wildlife Federation (SCWF).

In 2019, Keck launched Project Prothonotary, an ambitious effort to construct and install nest boxes that mimic natural tree cavities. Four years later, he and his colleagues have put up some 500 boxes on federal, state and private land statewide, from the coastal plain to the foothills of the Blue Ridge Mountains. At one site, Congaree Creek Heritage Preserve, Keck and South Carolina Department of Natural Resources staff brought in and installed these boxes with predator guards.

Though the pandemic postponed plans to have volunteers monitor the newly installed boxes, Keck and his colleagues from SCWF and the U.S. Forest Service have visited many of the sites themselves. What they’ve found has been hopeful: Half or more of the boxes now host warblers, says Keck.

At one site, Sumter National Forest, Keck and partners discovered prothonatary warblers nesting in 70 percent of the new boxes—including this clutch of days-old hatchlings.

At Old Santee Canal Park, this male warbler was delivering a caterpillar to his hungry chicks. So far, public response to the project has been encouraging. “Once people hear about this bird and the challenges it faces, they are super eager to install our nest boxes,” says Keck. “It really has given me hope.”