The golden-winged warbler’s preferred habitat along the A.T. falls on high-elevation shrubby meadows feathering into deep forests, such as the landscape on the North Carolina-Tennessee border. Photo by Chris Gallaway / Horizonline Pictures

Sustaining critical HABITATS along the A.T. benefits the threatened golden-winged warbler and biodiversity overall

By Marina Richie

Imagine a scene in early April as a wave of A.T. thru-hikers backpack north from Springer Mountain, Georgia. Thousands of miles to the south, imperiled golden-winged warblers are fueling up for their perilous flight from tropical forests of northern Venezuela and Colombia to the Appalachian Mountains. Some have spent the winter in coffee plantations that carry the Smithsonian Bird Friendly certification and protect biodiversity. In the tropics, the warblers flit among trees dripping with ferns, orchids, and moss as they probe for insects. But those forests can be increasingly hard to find.

Named the 2024 Bird of the Year by the American Birding Association, the golden-winged warbler dwells in two worlds. All neotropical migratory birds nesting in North America and wintering in Latin or South America remind us that we are linked on one life-giving blue planet spinning around the sun.

When ready, the warblers will flare their golden wings and flutter off into the night. Most warblers migrate while we are sleeping. Ahead lies a dangerous crossing of the Gulf of Mexico. Entering Florida, the songbirds will confront obstacles their ancestors never knew, like disorienting artificial lights and communication towers. But some will avoid deadly collisions to navigate all the way to the very home they left the autumn before.

The trail of a golden-winged warbler is a skyway. Shelter lies in stopovers where a bird can find trees, shrubs, and insects to eat. The destination is a nesting haven. Along the A.T., those habitats fall on high-elevation shrubby meadows feathering into deep forests. While the warblers migrate and nest all the way up the Appalachians into southern New England, the ATC focuses on improving key habitats in Virginia, North Carolina, and Tennessee.

Golden-winged warbler caught in flight. Photo by Lorie Shaull, Creative Commons Attribution 2.0

The ATC’s efforts on behalf of the golden-winged warbler are vital. Numbers have plummeted by more than 98 percent for the southern Appalachian Mountain nesting birds. A second population is faring better. Those birds spend winters in Costa Rica and summers in the Great Lakes of the northern Midwest and Canada. But overall, the golden-winged warblers as a species have declined by 66 percent since the 1960s.

Map provided by eBird (www.ebird.org)

The primary reasons for drastic declines are a loss of both breeding and wintering habitats: In addition to a shortage of ideal shrubby meadows within a forested landscape for nesting, deforestation in Central and South America threatens their winter homes. Other threats include hybridization with the blue-winged warbler, collisions with cell towers and windows, outdoor cats, and climate change. This litany of risks has made the species one of the highest conservation priorities of all forest birds in the United States, according to the Golden-winged Warbler Working Group.

Keeping Meadows Messy in Virginia

Conner McBane, ATC’s natural resource manager, is skilled at shaping shrub meadows that edge into young and mature forests in southwest Virginia. The patterns he seeks to create are guided by the warbler’s definition of perfection — unkempt, messy, and scruffy.

One tool for making a beautiful mess is a large mower called a skid steer. For anyone who has known the tedium of mowing manicured lawns, this task is far more interesting.

“It’s not like mowing your lawn,” he explains. “You have to avoid the milkweed, the monarda, the goldenrod, and some of the blackberries. We’re creating a light touch of a mosaic and mowing without a pattern.”

The patchy mowing reflects a major shift from a decade ago when the ATC and the U.S. Forest Service (where the Trail passes through national forests) managed open meadows primarily for views.

“While well intended, A.T. managers then mowed everything in the openings to make people feel like they were in ‘Little House on the Prairie,’” McBane says. “And they often mowed in May, June, and July, causing significant impact to biodiversity.”

The change to being wildlife stewards took time to educate people and to fine-tune new management prescriptions. The resulting tangled and multi-layered habitats offer homes for at least 50 wildlife species including other declining birds, like yellow-breasted chats, chestnut-sided warblers, and vesper sparrows.

Butterflies at risk of extinction benefit too. Monarchs lay eggs on milkweed plants that are the sole hosts of caterpillars. The Diana fritillary, a showy big butterfly of the southern Appalachian Mountains, relies on edges and openings among moist mountain forests and only breeds if the wooded margin is intact.

The monarch butterfly and chestnut-sided warbler are among the threatened or declining species that benefit from the habitat preferred by the golden-winged warbler. Photo above left by Lasclay/Unsplash; photo above right by Chris Gallaway / Horizonline Pictures

Old Farmlands as Ideal Habitat

Any sighting of a golden-winged warbler arriving in a nesting area is a cause for celebration. The 200 acres surrounding Virginia’s Knot Maul Branch Shelter had once been farmland. Known as the Tilson tract, it was acquired by the ATC and the Forest Service in 2009 to expand the narrow Trail corridor. The area has gradually grown into ideal habitat.

“Now, the Tilson tract is the biggest hotbed of golden-wings in the George Washington National Forest,” McBane says.

Each nesting territory is about five acres — the size of a baseball field, but nothing like it in appearance. A female weaves her nest on the stems of a goldenrod or a blackberry bush and far down at the base for concealment. Each delicate cup holds three to six eggs.

Once the chicks hatch, they need plentiful protein. Native trees hosting abundant caterpillars play a key role. Parents fly back and forth from the nest with insects. The male also likes to sing and defend a territory from a nearby tree. But not just one tree in the opening will do. The best scenario is five to 15 trees per acre. When the chicks fledge, the families fly into adjacent mature forests for food and shelter.

wild ponies in Grayson Highlands State Park. Photo by Joshua T. Moore

To maintain these ideal conditions, McBane follows guidelines from the Golden-winged Warbler Working Group for thinning of certain black cherries, locust, and black walnut trees, but never of mature hardwoods. He concentrates in areas that are close to the desired conditions with dense shrubs like hawthorn and blackberries.

He’s surprised that the higher-elevation meadows of the A.T. in Virginia, like Mount Rogers and Whitetop, lack golden-winged warblers, because the conditions seem right for them. McBane’s work to enhance habitat in some of the highlands is helping other wildlife like the Appalachian cottontail and overall diversity. He hopes one day the golden-wings will find a nesting haven there, too.

There’s another reason to pay close attention to the highest elevations on the A.T. As climate change warms the planet, many species are moving up in elevation or north to find cooler refugia. The golden-winged warbler’s range has already shifted northward in recent decades. Those mountainous habitats may also lessen the chances of hybridizing with the closely related blue-winged warbler that tends to nest lower down.

Dappled sunlight graces the A.T. as it traverses Max Patch on the border between North Carolina and Tennessee. Photo by Chris Gallaway / Horizonline Pictures

Singing the Wrong Song?

Tipping back his head, a golden-winged warbler poured out a melody worthy of May wildflowers on Max Patch that straddles the North Carolina and Tennessee border. But something was off on this fine morning. The jaunty male was singing the wrong song. Instead of a buzzy beeee…bz-bz-bz, the warbler riffed bee buzzzz.

Matt Drury, the ATC’s associate director of science and stewardship, focused his binoculars on the tiny bird with a dash of yellow on wings and head feathers, a black eye streak, and a chickadee-like black bib. Yes, this golden-winged warbler was decidedly belting out a blue-winged warbler tune.

Baffled, Drury turned to Avery Young, a biological science technician with the Pisgah National Forest. They stared and listened. This was not how they imagined the start of their field day recording birds and hoping to hear and see golden-winged warblers.

Where an A.T. hiker might whistle or hum a favorite tune for fun, a male warbler needs to sing at least a version of his species’ song to attract a female and defend a territory. Would this male golden-winged warbler shift to the right one? Could he?

The two warbler species are so closely related they can mate and produce offspring, known as Brewster’s warblers. This causes genetic dilution of both species — and is particularly problematic given the golden-wings’ diminished population size.

Later that day, Young found another golden-winged warbler singing the expected song in a 13-acre area between Max Patch and Buckeye ridge, where the ATC had recently completed a tree thinning to maintain views and improve the warblers’ habitat. That sighting was welcome news. Biologists estimate only 1,000 golden-winged warblers make it to western North Carolina, with fewer each year.

More than Warblers at Stake

At Max Patch, where heavy human use poses challenges to the sensitive meadows, Drury often lets the warbler’s needs for thorny blackberry thickets serve as a visitor use management tool. What better way to keep people on a trail than let the trailside berry bushes grow high?

“Those are some of the thorniest, meanest blackberry I know,” Drury says. “That’s the best closure possible.”

Mowing every two to five years is about right, Drury said, along with other enhancements conducted in a partnership with the Pisgah National Forest. While Max Patch is a focus, he’s also giving warbler habitat a boost at other places along the Trail including Hump Mountain and the Upper Laurel Fork area of Tennessee.

Drury stressed that the ATC’s goal is to benefit biodiversity. Like McBane in Virginia, he noted how many other species are served by maintaining the scruffiness, edges, and mix of shrub and forest. The wildlife seeking the havens of golden-winged warblers extends beyond songbirds and butterflies. Black bears feast on blackberries. Bobcats prowl the thickets seeking cottontail rabbits. Hungry ruffed grouse nip the leaves of shrubs.

Imagine this scene: First light enters the Knot Maul Branch Shelter in Virginia where a couple backpackers stir in their sleeping bags, wakened by the dawn chorus. Among the serenading birds is a golden-winged warbler heralding the day with the right song on a day where everything will go… just right.