DULUTH — Four woodcock that grew up in northern Minnesota are spending their winter basking in the Gulf Coast region sunshine and are checking in every five days to tell us about it.
They are part of an ongoing study of the migratory forest birds that hopes to shed more light on habitat needs, not only where they nest in the summer, but also where they spend nearly half the year down south.
Three woodcock hens were fitted with tiny satellite transmitters last summer near Hackensack, Minnesota. One disappeared within a week, with no sign of the transmitter. But the other two survived, managing to avoid predators all summer and hunters in the fall, with one now wintering near Shreveport, Louisiana, and the other not far away near Texarkana, Texas.
ADVERTISEMENT
Two young males got their transmitters in September near Remer, Minnesota. One is now wintering near Muskogee, Oklahoma. The other is the outlier in the group, heading east to Ohio before heading south to spend the winter in Alabama.
Minnesota woodcock generally will stay north until snow covers the ground, and thus covers their source of earthworms to eat. They will return north in late March or early April.
The study, headed by Alexis Grinde at the University of Minnesota Duluth's Natural Resources Research Institute, started in 2019. It’s been deciphering the type of forest that woodcock need to raise their young and found that the little birds with the long bills need lots of logs and branches on the ground to hide from predators.
RELATED: Hunting for answers on forest bird decline
The original research used short-distance radio transmitters to track the birds across a relatively small area near their nests for just a few weeks. Now, satellite transmitters will offer precise, long-distance locations every five days for nearly a year.
Researchers knew Minnesota woodcock liked the Gulf Coast in general in winter. But it hadn’t been clear precisely where they go and what kind of habitat they use when they get there.
The birds didn’t take long to make their trip south. Because the transmitters report only once every five days, to conserve battery life, it’s unclear exactly how direct their flights were, but they took between five and 15 days to travel roughly 1,000 miles.
ADVERTISEMENT
“It’s interesting that three of them ended up pretty close to each other. … Then we have that other immature male fly way off to the east, near Columbus, Ohio, before going south,’’ Debbie Petersen said.
Petersen, a certified bird bander, science teacher and naturalist from Walker, Minnesota, has trained her Gordon setter hunting dogs to find woodcock not just in the fall for sport, but in the spring and summer for research. It’s the dog’s ability to find the birds, and Petersen's skill at capturing them by hand or in nets, that allows researchers to attach the transmitters to study the birds.
The transmitters weigh just 4.1 grams, or 0.15 ounce. An average woodcock weighs about 7 ounces. The units are fastened to the bird with a material designed to wear out so the transmitter falls off after several months.
The overall goal of the study was to find out why woodcock are doing fairly well in northern Minnesota forests, but are declining steadily across much of their U.S. range. It appears that Minnesota offers ample young forests, created by steady logging and the demand of the region’s wood products industry, which helps create one key component of woodcock habitat.
The birds seem to do best where they can get to multiple different types of forest in close proximity — young, medium and old trees, big and small, used for feeding, nesting and cover at various times of summer and early fall. If scientists can figure out what types of forest habitat promote better nesting and survival, then they can provide those results to foresters and land managers to help conserve the species in other states, Grinde said.
ADVERTISEMENT
RELATED: University of Minnesota Duluth woodcock study finds habitat needs
Now, with satellite transmitters, the goal is to “fill in even more of the unknowns about the life cycle of this bird,” Grinde said. "We know what kind of habitat they nest in. But we really didn’t know anything about what kind of places they prefer the rest of the year.”
Grinde said the data provided by the satellite transmitters already has revealed an interesting quirk. Two of the woodcock in the study first flew farther north in Minnesota before later heading south. It’s unknown if this is an unusual move or is a common characteristic — maybe birds scouting out new territory for nesting the next year.
“We’re also seeing some really fine-level data on where they are spending the winter,’’ Grinde said, noting the researchers get precise locations from the transmitters and then can check those spots on Google Earth and other land cover sites.
“There’s one of them hanging out in what looks like a housing development. … And we’re thinking, what the heck is it doing there?’’ Grinde said. “But the other ones are in what look like wildlife management areas, spots where you might expect them to be.”
John Myers reports on the outdoors, environment and natural resources for the Duluth News Tribune. He can be reached at jmyers@duluthnews.com .
