Buckner Memorial Preserve, Rutland County, Vermont

Shrub Clumps and Feathered Edges Help Rare Warblers

"Good golden-winged warbler habitat has clumps of native shrubs near areas of mature forest," says Mark LaBarr of Audubon Vermont. At Helen W. Buckner Memorial Preserve at Bald Mountain, in West Haven in west-central Vermont, Audubon Vermont is working with The Nature Conservancy, which owns the preserve, to improve the habitat for those warblers as well as a large suite of other wildlife.

In recent decades, the golden-winged warbler population has fallen by 70 percent across the species' North American range, with an average 7 percent annual decline in Vermont over the last 25 years. The main reason is a loss of young forest habitat near mature woods. Such habitat vanishes when forest naturally succeeds shrubland, and when young forest grows older over time.

Clump of gray-stemmed dogwood offers excellent native-shrub habitat to golden-winged warblers and other wildlife on Buckner Preserve./Audubon Vermont

According to surveys conducted by Audubon Vermont, the shrubland areas of Buckner Preserve support the highest concentration and the largest remaining population of golden-wings in the Green Mountain State. In fact, Vermont has the only populations reported from any New England state. Those rare warblers won't be the only beneficiaries of the habitat work begun in 2016 at Buckner: "Whip-poor-wills, American woodcock, indigo buntings, brown thrashers, kingbirds, field sparrows, blue-winged warblers, prairie warblers – those are just some of the birds that will be helped by the habitat improvements," LaBarr says.

He waves his hand toward a rolling landscape of weed-strewn fields dotted with clumps of shrubs, the fields backing up against mature woodlands. "Our goal is to encourage the growth of a native shrub community and to create patchiness in the shrubs' overall growth pattern," he says. As the management work proceeds, shrubs and saplings will stand 3 to 13 feet high and will cover 30 to 70 percent of the management units planned for Buckner Preserve.

Conservationists will use grinding machines, chainsaws, and brush-hogging to keep vegetation at the right density and to discourage invasive non-native shrubs such as Asiatic honeysuckle and buckthorn. They'll also feather the edges of the mature woods, so that no hard line exists between woods and shrubby fields but rather a mix of shrubs and small trees. In the fields, they'll leave a few widely spaced trees for male golden-winged warblers to use as singing perches, and for golden-wings and other birds to feed in. Says LaBarr, "This type of management is way more subtle than just going into a wooded area and making patch cuts to stimulate the growth of young forest."

Surveying habitat for warblers in Vermont's Champlain Valley./T. Rogers

Murray McHugh, The Nature Conservancy's Critical Lands Manager for southern Vermont, accompanied LaBarr on a tour of the habitat improvements recently launched at Buckner. At almost 4,000 acres in both Vermont and adjacent New York, Buckner is a large and ecologically diverse natural area. The golden-winged warbler habitat work will take place on 16 management units totaling 185 acres. Over the next three to four years, TNC and Audubon Vermont will patiently mold the habitat by grinding down and chain-sawing unwanted invasive shrubs, then use herbicides to spot-treat sprouts that emerge from the invasives' root systems. They'll also brush hog the management units every three to five years, so that the shrubs remain in discrete clumps and don't merge with one another to form a shrub monoculture that would be less suitable for golden-wings.

TNC's McHugh points out that black rat snakes (listed as a threatened species in Vermont) and ribbon snakes use the old-field habitat, too. "Some of the fields will be managed for leopard frogs, which the snakes prey on. There's a snake study going on here now," he says, explaining that "snake slates" have been set out in likely spots. The slates grow warm under the day's sun; at night, snakes shelter under the slates to enjoy the warmth, and biologists can lift the slates to see which and how many snakes are using the habitat.

Buckner Preserve, with its many and varied habitats, is home to a great assortment of wildlife including peregrine falcons, ospreys, bald eagles, wild turkeys, black-billed cuckoos, black bears, coyotes, porcupines, and five-lined skinks, Vermont’s only lizard.

Machine grinds down non-native invasive shrubs in old field, giving native shrubs a chance to compete and shaping the habitat for golden-winged warblers./M. Fowle

The golden-winged warbler management units are on the former Galick Farm and Tim's Trail areas of the preserve. High-school students from Stafford Technical Center in nearby Rutland, Vermont, used chainsaws to cut down honeysuckle and buckthorn in both areas. Another partner, the Wildlife Management Institute, is funding the mechanical grinding and herbicide work aimed at suppressing the invasive shrubs.

"This approach gives native shrubs an advantage in competing with the non-native varieties," LaBarr says. "Some of the native shrubs and small trees that will increase and spread in the fields and on the field edges include alder, gray dogwood, nannyberry, hawthorn, serviceberry, and prickly ash." In general, native varieties provide more diverse and more-nutritious foods for birds, including fruits that remain on the plants longer and offer sustenance to wildlife over a more-extended period each year.

The habitat work on Buckner Preserve is part of Audubon Vermont's Champlain Valley Bird Initiative. The southern Champlain Valley, where Buckner Preserve is located, has been identified as a conservation focal area for the golden-winged warbler by the Golden-Winged Warbler Working Group, a national partnership working to protect the species and, ultimately, to prevent its having to be placed on the federal Endangered Species list.

"Here in the Champlain Valley," says LaBarr, "we're working with private landowners, foresters, communities and municipalities, and nongovernmental organizations like The Nature Conservancy to help resident and migratory birds by creating and improving shrubland and young forest habitat." Low shrub areas are vanishing rapidly in the valley – and also in Vermont and much of the East – as old farm fields gradually fill in with trees and become forest, or as they get turned into houses and manicured lawns. (Much of this work has received funding from the USDA Natural Resources Conservation Service, through a National Fish and Wildlife Foundation grant.)

Audubon Vermont biologists Margaret Fowle and Mark LaBarr attach a geolocating device to a male golden-winged warbler at Buckner Preserve./M. McHugh

"When people manage areas of low native shrubs to keep them around and keep them healthy," LaBarr says, "they not only help the wildlife that needs this kind of habitat, but they can also preserve long-range views of mountains or an attractive local landscape" – a factor that has persuaded more than a few landowners to join with Audubon Vermont in conducting this sort of management.

In tandem with the habitat improvements, Audubon Vermont participates in scientific monitoring work at Buckner Preserve. In spring, LaBarr, Margaret Fowle, and other Audubon Vermont biologists capture golden-wings in mist nets, record data on their weight and health, and attach to the birds tiny backpacks fitted with geolocator units. After the breeding season, these electronic devices track the birds' travels as they wing south to spend the winter in a range that stretches from Guatemala to Colombia.

When the birds return the following year, the conservationists will try to catch them again, remove the geolocators, and download information captured by the devices. That information will help biologists learn about migration routes and pinpoint important habitats that the songbirds use en route to and on their wintering grounds.

It may also help biologists determine whether the golden-wings that breed in the Champlain Valley spend the winter with golden-wings from the Great Lakes states or with those that breed in the Appalachian Mountains. (Habitat loss and population decline have caused the two ranges to become separate.) Such data will build a better picture of golden-wing genetics, overall health, population, and habitat needs.

Not only will the habitat work at Buckner Preserve boost golden-wing numbers, it will also offer human visitors a chance to see what the birds' habitat looks like and to observe the rare warblers as they breed, build their nests, hatch young, and prepare to head south in autumn. The management efforts will also boost the diversity and populations of many other wild creatures: exactly what a Young Forest Habitat Demonstration Area is supposed to do.

Partners and Funding

Partners working together to improve the habitat on Buckner Preserve include Audubon Vermont, The Nature Conservancy, and the Wildlife Management Institute. The Nature Conservancy is interested in bringing in new partners and funding for this and other habitat-related projects.

For more information on partnering, and to plan a visit to see the habitat work, contact Murray McHugh, Critical Lands Manager, The Nature Conservancy (Southern Vermont Office), 348 Bentley Ave., Poultney VT 05764, 802-884-8165 x 23, mmchugh@tnc.org

To visit the Helen W. Buckner Memorial Preserve at Bald Mountain: From Whitehall, NY, take Route 4 east; from Rutland, VT, take Route 4 west. Then from Route 4, just east of Whitehall village, turn north onto Route 9A across from the Bittersweet Plaza. After about one mile, turn left onto Route 9 at the T intersection. Take the first right onto Route 10 (Doig Street), then turn left onto the dirt road (where the paved road curves right). Cross the bridge and bear left. The Tim's Trail parking area is 0.7 miles down the dirt road on the right near some large rocks. Conservation partners have begun habitat management work in the first shrubby areas past the initial open field, in the vicinity of a small pond, and along the forest edge.