Nearly half the golden-winged warblers in the world are in northern Minnesota right now for the summer breeding season.
Their habitat shrinking, the tiny birds have become the subjects of a two-year research project that could help determine whether they should be listed as a threatened or endangered species.
See more photos of the golden-winged warbler research team. You can read more about the effort to save the golden-winged warbler here.
The research, conducted by the Minnesota Cooperative Fish and Wildlife Research Unit, could have a larger impact as well as scientists learn more about habitat changes affecting other species, too.
"A golden-winged warbler is kind of the proverbial canary in the coal mine," says Henry Streby, a researcher with the University of Minnesota, which is a member of the research unit. "If they're not doing well there's something wrong with the area because they're tiny and sensitive. And by studying golden wings and finding out what's best for them it would definitely benefit many other birds that have very similar habitat requirements."
The golden-winged warbler population is steadily declining. The largest remaining group is in Minnesota, and one of the best places to study them is the Tamarac National Wildlife Refuge north of Detroit Lakes. Researchers are also collecting data on the songbirds at the Rice Lake National Wildlife Refuge in northeast Minnesota and at a site in southern Manitoba.
At 6 a.m. on a recent June morning, Streby was sitting on the ground in a brushy clearing, carefully holding a tiny female golden-winged warbler in his hand and painstakingly attaching a tracking device to its back. He's in the first year of a two-year project.
It's not easy to study a bird that's four inches long and weighs the same as three pennies. Researchers spend hundreds of hours carefully searching for the tiny nests of leaves built at the base of small shrubs.
They use a recorded call to lure the male with its striking yellow markings into a net.
By attaching radio tracking devices to the warblers, Streby is uncovering some of the birds secrets.
He says scientists have long focused on the brushy habitat where the birds nest.
"That's where they are in the few hours in the morning during the breeding season when the males are singing. And that's the easiest time to study them because they're yelling at you, 'Here I am. Study me all morning.'
"And then they get quiet and go away and forage in the mature forest. But there's no way for anybody to know that until we put transmitters on them."
The study is part of a global effort to save the songbird. University of Minnesota Crookston Professor John Loegering is one of the members of the Golden Winged Warbler Working Group.
He says the U.S. Fish and Wildlife Service is taking public comments on a petition to protect the golden-winged warbler.
"We hope we can figure out what makes them tick so we can design or implement conservation strategies to improve or bolster that population," Loegering said.
The songbirds need mix of habitat — mature forest and brushy clearings. Human development often creates something very different.
"Humans move into the area and like to set whatever habitat they particularly want in the landscape," Loegering said. "And that certainly degrades the habitat from a golden wing's perspective. They sort of need that dynamic, ever changing habitat."
Streby says changing public perceptions about forest habitat might just be the only change than can save the golden-winged warbler.
"I think when people are driving up to their lake cabin and they see a clear cut in the middle of an extensive mature forest they see it as a scar on the landscape," Streby said. "But if that's not there, those birds won't be there."