Each spring, Golden-winged warblers fly from Central and South America to the Eastern United States to mate and nest. But over the past 30 years, fewer and fewer of these little songbirds have been found in their traditional breeding range. That's because people, vegetation and some not-so-distant relatives are encroaching on their turf. The Allegheny Front's Ann Murray spent time with Pennsylvania researchers and land managers who are trying to stop the Golden-wings' decline. It's the second in our series "Protecting Pennsylvania's Wildlife."
OPEN: Each spring, Golden-winged warblers fly from Central and South America to the upper Midwest and Eastern United States to mate and nest. But over the past 30 years, fewer and fewer of these little songbirds have been found in their traditional breeding range, especially in the East. That's because people, vegetation and some not-so-distant relatives are encroaching on their turf. The Allegheny Front's Ann Murray spent time with Pennsylvania researchers and land managers who are trying to stop the Golden-wings' decline.
MURRAY: Jeff Larkin and his grad student, Joe Grata, have been in radio contact since sun up.
LARKIN: Hey there Joe.Did you get any points on pink blue?
GRATA: Yeah I got ten points on that bird.
MURRAY: They're in hot pursuit of Golden-winged warblers, one of the most threatened songbirds in the eastern United States. Larkin is a conservation biologist at Indiana University of Pennsylvania. He says most researchers agree the best way to save golden wings is to make sure they have suitable breeding habitats. That's why he's in the field.
LARKIN: Giving forest managers and other land managers an idea of what particular habitat characteristics they need to be managing for is the ultimate goal of this particular project.
MURRAY: Larkin's project is a multiyear study of Golden-winged warblers in two areas where they breed and nest in central Pennsylvania: Bald Eagle State Park and Sproul State Forest . NAT SOUND: WALKING THROUGH THICK BRUSH
This morning, Larkin, Grata and other research techs are spread out along a thin two mile long strip of the park. This is their second season in the field. After trudging through dense, rain soaked brush, Larkin hits a clearing.
LARKIN: I just heard a golden winged warbler back in this direction. I'm probably going to leave you in the dust.
MURRAY: Larkin takes off toward a large tree at the clearing's edge. When the four-inch long bird lights on an upper branch, Larkin whips out his binoculars and discovers this male was banded with identifying colors last spring. He make notes, gets global positioning points and flags the tree. Later on, his team will map the location.
LARKIN:. Collectively we'll probably visit this guy 8 to 10/12 times this season and hopefully also find his nest and be fairly confident after that many visits that his territory is delineated.
MURRAY: Delineating each golden wing's territory takes time and careful observation. Male golden wings mark their territory by flying from tree to tree. They like open areas with grasses, low shrubs for ground nests and trees at the periphery. These so called "early-successional" habitats are harder and harder for golden wings to find. That's because abandoned farmland is being developed and Eastern forests' are maturing and filling in open spaces. This kind of habitat loss accounts for big declines in populations. But shrinking habitat isn't the only reason about seven percent of the state's golden wings disappear each year.
NAT SOUND: POUNDING IN POLES FOR NET: Later in the afternoon, the team sets up a fine mesh net to catch an unbanded golden wing. Joe Grata has perched a dummy warbler with a recording of golden wing songs in a shrub in front of the net. The territorial male golden wing swoops in for a fight and lands in the mesh.
MURRAY: While Grata and a tech, weigh and band the captured bird, Larkin explains that one closely related bird species has made inroads into some Golden-wing territories. In parts of the Northeast, Blue-winged warblers pose a biological threat in part because they're so darn attractive to female golden-winged warblers.
LARKIN: Theres evidence that Blue-winged warbler males are more likely to get a Golden-winged warbler as a mate than a Golden-winged warbler male is to get a Blue-winged warbler as a mate.
MURRAY: Hybrid offspring look like Blue-wings. Over a few years, these more adaptive birds can crowd out golden winged warblers. The researchers are trying to figure out exactly what vegetative mix attracts blue-wings. Larkin's also cataloging what grasses, shrubs and trees are found where Golden-wings are successfully breeding and nesting. All this information will be used to manage experimental plots for golden-winged habitat in Sproul and Bald Eagle. Park manager John Ferrara will help Larkin with this part of the project.
FERRARA: Part of our goal is to return much of those areas into an early-successional stage through manual manipulation.
MURRAY: The park will begin by mowing and treating experimental plots to remove invasive shrubs and groundcover. There might be other tweaks with grasses and trees to open up these sites even more for Golden-wings and other animals like the American Gamecock and the Appalachian cottontail. Larkin's going to share what he learns with other researchers, land managers and government agencies. At a meeting of the conservation group Partners In Flight, Randy Dettmers, a migratory bird biologist with US Fish and Wildlife, says Larkin's research will be a regional model.
DETTMERS: In terms of parts of West Virginia, in Virginia and New York, the things that happen in Pennsylvania will be very instructive.
MURRAY: Back in the field, Jeff Larkin has had a pretty successful morning. He's on a walk to confirm golden wing territory in Sproul State Forest. An earlier fire in the forest has created an open area that golden wings like. But Larkin says he waffles between optimism and concern for the future of the species here in the state.
LARKIN: The long term prospects for the Golden-wing in PA, I'm going to say I'm hopeful but it's going to take a lot of work. It's going to take a lot of collaboration and it's going to take a lot of thinking how we should best manage these areas.
MURRAY: For The Allegheny Front, I'm Ann Murray.