Tracking the American woodcock

[h2ofwlr]

By Dave Orrick, St Paul Pioneer Press
Posted: 10/18/2014 04:04:46 PM CDT

Photos and video: http://www.twincities.com/sports/ci_267 ... n-woodcock

SHERBURNE NATIONAL WILDLIFE REFUGE -- Clusters of headlamps bob through the field of grasses and young willow shoots well after dark.

"We got one," calls a voice from one cluster. "You guys?"

"Six!" is the cheery response.

The two clusters meet amid what might to the outsider look like a series of badminton nets erected for who knows what purpose. The headlamps illuminate hands holding half a dozen cloth sacks, each occasionally squirming.

Inside each is a live American woodcock.

This was the scene this month as a team of researchers and volunteers set out to catch woodcocks and fit them with small satellite transmitters. The badminton nets are "mist nets" that birds simply fly into unawares as they head toward evening roosting grounds.

The project, headed by the U.S. Fish and Wildlife Service, aims to unravel lingering mysteries surrounding the odd and diminutive migratory game bird.

With a long beak and toes, the American woodcock looks similar to a shorebird. Yet it lives generally in the woods, using its flexible beak -- which it can open just at the tip if it so desires -- to forage on insects and grubs in the damp forest floor. Adding to its idiosyncrasies: It's eyes appear sort of backward; in fact, its brain is essentially upside down.

And then, of course, there is its name, which can't help but evoke a chuckle in boys of a certain age. Its alias is downright silly: the timberdoodle.


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A popular quarry for upland hunters -- ruffed grouse hunters frequently encounter woodcocks in fall coverts of young birch and poplar -- they breed across much of the northern Midwest, Northeast and southern Canada, and migrate as far south as Louisiana and Texas. Scientists know this much from banding data: Birds are affixed with identifying bracelets that are reported, usually, after a hunter shoots it dead. It's a time-tested method, but one with obvious limits, namely that the scientist learns only two geographic locations: where it was banded, and where it was shot.

Much of the migration remains a mystery.

"From banding data, we have a pretty good idea where birds from Minnesota, Wisconsin, Michigan and New England migrate to in the winter," said Tom Cooper, migratory bird biologist with Fish and Wildlife who is among those heading up the project. "But we don't know how many stops they're making, how long they stay at those stops, how long it takes them to get from where they're breeding to where they're ultimately breeding.

"So this project, we're hoping, will give us some of those answers, and also help us delineate some of those areas that may be important for woodcock that we don't know about, so we can look at the conservation and habitat management in those areas."

By analogy, decades of effort has gone into restoring and maintaining the water quality of Lake Christina in western Minnesota for its long-documented importance as a stopover for canvasback ducks. It's nearly impossible not to notice the massing of 80,000 ducks on a lake.

But Cooper said it's possible similar places exist for woodcock that no one knows about. After all, the nighttime fluttering arrival of ground-dwellers, whose primary defense is camouflage, might go unnoticed in some scrubby backwoods.

The area where Cooper has had success in Sherburne NWR, near Zimmerman, is surprisingly less dense than typical cover hunters might associate with woodcock. That's the result of cattle grazing the area, another example of federal officials allowing commercial ranchers to use certain fields to maintain ecosystems that evolved when bison and wildfires routinely kept growth down.

"We didn't realize what a tremendous help it (grazing) would be," said Tony Hewitt, Sherburne's wildlife biologist, as we walked through areas of head-high willows with open pockets wide enough to twirl with outstretched arms. Evidence of woodcock feeding -- holes poked by their beaks -- was everywhere in the exposed soil.

Hewitt is aware that such grazing practices are not without critics, who worry that wildlife habitat could become publicly subsidized cattle ranches. "We're not doing this to feed cattle. It has to be a habitat-management tool."

Cooper aims to fit some 40 woodcocks with satellite transmitters, which are less precise than true GPS units but nonetheless transmit frequent location updates that researchers can monitor from a computer in an office.

The solar-powered transmitters are worn on the bird like a lumbar pack: They're looped around the upper legs and sit on the lower back, so they don't interfere with the wings.

Early data from six birds last fall suggests that they're following migratory routes previously suggested by banding studies. The project is too nascent to draw larger conclusions yet, Cooper said.

And yes, Cooper's teams have established that woodcocks can carry the 9-gram units throughout their migration.

Last fall, one bird was fitted with one in Minnesota's Tamarac National Wildlife Refuge. Starting Oct. 22, it carried the thing south some 1,100 miles, making at least three stops along the way, until it reached its wintering area in east Texas Jan. 14. In mid-February, it started back north, arriving safely at Tamarac in the spring.

Still, 9 grams is a hefty load for a small woodcock, and researchers limit their subjects to the largest birds, females of 200 grams or more. (That ratio -- 4.5 percent of body weight -- is actually higher than the generally recommended payload of 3 percent, and Cooper said he's eagerly awaiting a supply of 5-gram transmitters.)

Of the six timberdoodles captured on this recent outing, none were more than 200 grams, so the transmitters remained unused. Instead, those birds were banded, low-tech style.

Then researchers placed the birds in their outstretched hands. They alighted in the way that only woodcocks do, with a high-pitched fluttering from their wings, off into the night.