How One Underappreciated Habitat Is a Boon for Birds

Never thought much of thickets? Conservationists aren't surprised. Brushy and tangled, they lack the classic beauty of old-growth forests, sweeping grasslands, or towering mountains we tend to hold dear. But scientists agree they're one of the most critical habitats in the Northeast—and not just for the suite of fast-declining species like American Woodcock, Ruffed Grouse and New England cottontail that make their home there year-round, but also for millions of migratory songbirds that depend on their fruit-rich largess every autumn.

The problem is that as shrublands have disappeared—replaced by maturing woodlands, bulldozed by developers or brush-hogged by homeowners who want to tidy up the view—few have noticed or cared. But that may finally be changing. A number of major regional initiatives to protect and create early successional habitat, driven by concern for species like Prairie Warblers, Brown Thrashers, Eastern Towhees and Golden-winged Warblers that require it, are gaining ground.

Restoring Shrublands for Birds

The most dramatic sign of this newfound respect came early this year, when the U.S. Fish and Wildlife Service proposed the creation of Great Thicket National Wildlife Refuge, encompassing more than 15,000 acres across six states, from eastern New York to southern Maine.

The refuge still must clear several hurdles, including agency approval, but the focus on shrubby, early successional woodlands can't come a moment too soon, say conservationists who have been trying to get the public to pay attention to a critical but overlooked ecosystem.

"I feel like the Lorax—'I speak for the shrubs, because the shrubs have no tongue,'" Scott Comings said with a rueful laugh. The associate state director for the Nature Conservancy in Rhode Island, Comings has focused for years on the importance of thickets, especially for migratory songbirds (even those that normally eat insects), which gorge on the fruit of arrowwood viburnum, winterberry, native dogwoods, poke and other native shrubs. Various Audubon chapters and state offices have also been involved in restoring pockets of shrubland all over the Northeast, including Audubon New York, Audubon Connecticut, and Audubon Vermont.  

Which birds stand to gain? "On the coast it's every single migratory songbird," Comings said. "Red-eyed Vireo, Magnolia Warbler, Ovenbird—you name it. There's at least 35 species of warblers, five or six species of vireos, all the thrushes, flycatchers—everything depends on the shrublands as they move south."

And that's just birds. The successional thickets support a remarkable array of mammals, reptiles, amphibians and invertebrates that used to be common, backyard creatures in the days when shrublands, too, were common—animals like box turtles, monarch butterflies and black racers. The New England cottontail, the region's only native rabbit, is now marooned in five isolated populations, thanks to the decimation of the habitat.

How the Shrublands Disappeared

Thickets used to be common. In presettlement days, fires (often set by Native Americans), hurricanes, and other natural disturbances created a mosaic of habitats within mature forests. But thickets really came into their own as old farms were abandoned in the 19th and 20th centuries and turned to early successional shrubland. As the thickets regrew, the Northeast became more and more a uniformity of even-aged forest instead of a mosaic, said Scott Hall, senior manager of bird conservation for the National Fish and Wildlife Foundation.

"Within those mature, 60- to 100-year-old stands, we've lost the different components that make forests rich, like these early successional habitats," Hall said. NFWF has been supporting several major initiatives to restore early successional habitat for woodcock and Golden-winged Warblers, he said, which can serve as umbrellas for the other, less iconic but equally important species the habitat supports.

The USFWS is soliciting public comment through March 4 on the Great Thicket NWR proposal. The comments will be reviewed, and a decision made later in the year on whether to ask Congress for authorization, according to Tom Eagle, deputy manager for the Eastern Massachusetts NWR Complex.

If Congress gives the okay, purchasing the land for the refuge from willing sellers will be a long process. "It could take 15, 20, 30 years to really get where we want to be," Eagle said. But the agency is already working with landowners, NGOs, and state agencies in the region to collaborate on restoring shrubland habitat on state and private land, an effort that has tremendous, immediate potential to help thicket-loving birds.

How to Help: You can learn more about the Great Thicket NWR proposal or comment on the plan here. Show your support of that plan here. 

Editor's Note: An earlier version of this article misstated that the proposal requires Congressional approval—it requires agency approval.