Biologists think Highland good habitat for Golden-winged Warblers

Monterey, Va. – (Audio clip of golden-winged warbler song)

That is the song of the male Golden-winged Warbler when he is on his nesting territory in Highland and Bath Counties. A group of field technicians and a graduate student from the Department of Biology at Virginia Commonwealth University in Richmond are working under the direction of Dr. Lesley Bullock this summer to see if they can understand more about where this threatened species prefers to nest. Their research has shown that it may be possible to actually call Golden-winged warblers into good habitat and get them to nest there. Dr. Bullock explains some of the goals of this research project.

“We always think of habitat selection being based on vegetation only,” said Dr. Bullock. “So birds are coming in where the vegetation is the way it should be for the species, but there could be other cues that they are using, such as the presence of another one of their species, also known as a conspecific. There have been other studies done with similar species showing that this is true. That if you put a recording out of the same species at certain times of the year, when they might be prospecting for new habitat, that you can successfully call them into previously unoccupied sites.”

Dr. Bullock talks about why this area is ideal for this type of research.

“There hasn’t been a lot done with species that are really threatened and in low densities, so while Highland and Bath Counties are hot spots for this species, they are really dispersed because their habitat is so patchy,” said Dr. Bullock. “They like blackberry thickets and abandoned farmland really where they are grazing with really low densities of cattle or maybe you haven’t grazed for a while and the blackberries have begun to come in and lots of goldenrod and things like that. So it’s those abandoned or low intensity grazing areas that are very patchily distributed throughout this landscape.”

For the past several years, the Virginia Department of Game and Inland Fisheries in cooperation with the US Fish and Wildlife Service has been working to increase Golden-winged warbler habitat in our area through cost-share programs like their Wildlife Habitat Incentive Program. Several landowners in Highland and Bath Counties have set aside parts of their properties and planted shrubs and trees to make those acres better Golden-winged warbler habitat. Dr. Bullock talks about how her team’s research will contribute to increases in Golden-winged warbler populations in Virginia.

“There’s really a lot of potential here for real conservation work here because this is a species that is being considered for listing under the Endangered Species Act,” said Dr. Bullock. “If we can prevent that, it would be a really good thing. So if we can increase the numbers of birds in this area in Virginia and throughout the range using something as simple as putting out playback at certain times of the year to pull them into suitable, but unoccupied, habitat, it would be wonderful. Or in places where we have put management on the ground, and management is pretty expensive. You go in and maybe you do a prescribed fire or you use a bush hog to make the habitat just right and then you have used all these expensive techniques and then the birds don’t come in. Maybe it’s because this social cue is missing, it could be a really good way to increase the bird’s numbers.”

Dr. Bullock describes what her graduate student and field technicians do during a typical day of collecting data.

“What we have been doing since May 1st is to go out and find out where these birds are, so we’re doing surveys,” said Dr. Bullock. “So it starts at sunrise, we try to be on the ground at sunrise, going to all of the places that have been previously mapped out as potentially good habitat. So the crew will go out, usually in teams of two, but then they will split up and do a survey. A survey lasts about nine minutes. It’s three minutes of silent listening, followed by two minutes of a type 1 Golden-winged warbler song and then a little silence followed by a type 2 song and then a little more silence. If we really want to increase our detection of these guys, it’s been demonstrated before that using these playbacks they’ll respond and fly right in.”

Dr. Bullock’s research is supported by a grant from the Virginia Department of Game and Inland Fisheries.