by Greg Hoch
An odd reclusive bird who delights those who see him and fascinate those who study him. — Guy de la Valdène on the woodcock in Making Game
It's a late afternoon in mid-April at Tamarac National Wildlife Refuge in northwestern Minnesota. On these 43,000 acres, hardwood and coniferous forests meet prairie, creating a tapestry of habitats and a diversity of wildlife. Tamarac is on the western edge of the range of the American woodcock, a cryptic and elusive bird that researchers are here to study.
Woodcock are declining across much of their range, except in Minnesota, offering wildlife experts here an opportunity to study a stable population. One of the most vulnerable times in a wild animal's life is its first few weeks, especially for birds that aren't yet able to fly. The researchers who've come to Tamarac hope to fill in some knowledge gaps about the specific habitats that woodcock broods use.
The American woodcock (Scolopax minor) is technically a shorebird—a family of birds most often seen on beaches, wetlands, grasslands, or tundra. However, the woodcock lives in the forest. Specifically, it prefers young hardwood forests, small forest openings, and brushy uplands. Many habitats that look scrubby and are hard for people to walk through will suit the woodcock.
Woodcock winter along the southern Atlantic and Gulf Coast, especially Louisiana. Although the species of trees are different there, the dense stands of scrubby vegetation are structurally very similar to northern aspen forests.
Zoologist William Hornaday called the woodcock the oddest-looking land bird in North America. It is a round-bodied bird with stubby legs, a ridiculously long bill, and enormous eyes. The tip of the woodcock's long, narrow bill is full of nerves for feeling around underground for something to eat. The upper bill is flexible so that it can plunge into the damp soil and grab beetle larvae and earthworms. Its huge eyes, which allow it to see at dusk and dawn, when it is most active, are set so far back in the head that the brain is rotated almost upside down to accommodate them. The woodcock's quirky behavior and appearance have inspired many nicknames, including mudbat, bogsucker, mud dabbler, bog borer, and the delightful timberdoodle.
Aerial Courtship. Male woodcock perform their sky dance at dusk each night through the spring across the Great Lakes region.
The male's arrival is silent. The woods are quiet, the only sounds the whisper of the wind and the low-frequency drumming of a distant ruffed grouse. Suddenly, a loud, nasal peent cuts through the air. A woodcock appears, peenting repeatedly and dancing on comically short legs. This small patch of ground in the forest clearing is his singing ground. Then, without warning, he spirals about 300 feet up into the night sky. He's a speeding black shadow in a cobalt sky against a backdrop of twisting dark branches. He's almost impossible to follow by eye, but not by ear.
As he spirals through the air, he makes a sound that many observers have described as a twitter. The outer primary feathers of the male woodcock's wings are narrower than its other feathers. When held apart during flight, the feathers vibrate as air rushes between them, creating the sound.
At the top of the spiral, the woodcock "tumbles like a crippled plane, giving voice in a soft liquid warble that a March bluebird might envy," wildlife biologist Aldo Leopold wrote in A Sand County Almanac. The bird peents loudly and performs his stomping dance. Then, without warning, he launches himself into the air for more spirals. Most nights this repeats over and over for an hour or more, longer when the moon is full.
Sky Watchers. Tonight, a group of 10 researchers meets in the Tamarac bunkhouse. Kyle Daly, a graduate student at the University of Minnesota, has watched for sky dances in several areas of the refuge on recent evenings. He has placed sets of three nets, each 10 by 36 feet, around singing grounds where he thinks we'll have the best chance of catching birds.
Daly and Wayne Brininger, the refuge biologist, assign people to different nets. Volunteer Terry Petro and I will watch two sets of nets about 100 yards apart along a forest road.
As any hunter or birdwatcher will attest, wildlife often show up at unexpected times, in unexpected places, or not at all. In contrast, the courting male woodcock is quite predictable. He begins his evening show precisely when the sky has the right amount of light, 0.05 foot-candles, or about 19 minutes after sunset. If we know when a male first peented last night, we can predict tonight's first peent to the minute. The location he chooses is also predictable: He will land within inches of where he was in previous evenings.
Daly's goal tonight is to catch woodcock hens when they come to observe and determine the suitability of a potential mate. He hopes the hens will fly into the nets and become entangled. Then Daly will outfit each hen with a radio transmitter so he can track her and her brood throughout the summer.
We spend the evening walking back and forth between the sets of nets about every 30 minutes. We want to check the nets frequently, but we don't want to disrupt the birds. On the last check of the night, by now completely dark, my furry, four-legged assistant trots ahead and stops with his nose an inch away from a net.
Now the fun begins: untangling a brown bird from black netting in the dark, working as quickly as possible to minimize stress to the bird. The woodcock flew into the net head first, so the bird must come out tail first. First, I free the feet and then wrap them in the first two fingers of my left hand. I work the netting from under the tail, over the back, around and underneath each wing. After I pull the last loop of netting over the top of its head, the bird is free of the net but still in my hand. I quickly place my right hand over the bird's back with the first two fingers held on either side of its neck and the rest of my hand wrapped around the bird, gently holding the wings against the body. In this position the bird can't struggle or hurt itself.
We attach a numbered aluminum band on one leg. Next, we measure the length of the bill. Less than 66 millimeters means it is a male, greater than 68 millimeters means female. If that isn't conclusive, we measure the length of the wing and the width of the three outer primary feathers. With these numbers and Greg Sepik's booklet called A Woodcock in the Hand, we can determine the gender of the bird.
To determine age, we examine the fifth to eighth secondary feathers on the back of the wing. If the feathers have a narrow, dark band near the tip and mottling on both sides, the bird is a juvenile. If the feathers lack that band and have mottling only on one side, the bird is an adult.
This bird has a relatively short bill, short wings, narrow outer primary feather, and mottled and banded secondary feathers. He's a first-year male. No need for a radio transmitter; Daly is putting radios only on hens. After we record the data, I simply open my hand and the bird flies off into the night.
Dog Work. Three weeks later, in early May, I meet Earl Johnson, retired DNR area wildlife manager from Detroit Lakes, and his English setter, Lars, at the refuge.
Using nets, Daly has already placed radio transmitters on several hens and is monitoring their nests. Once the eggs hatch, he'll use the hen's transmitter to find her brood and place a transmitter on one of the chicks. Then he can track the brood to determine the habitats they use through those first months of life.
With any wildlife research, one of the largest problems is studying enough individuals to make accurate conclusions. Today's task is to find additional broods using the dog, so Daly will have more birds in his study.
Within 20 minutes, Lars is on point in a thick stand of hazel. The hen flushes before we can drop a net over all the birds, but Johnson quickly moves in and scoops up the three chicks. Each gets a band, and one gets a very tiny transmitter.
To determine age, we measure the bill and apply a formula found in Sepik's booklet. The length of the bill in millimeters, minus 14, divided by two, tells us the age in days. These fluffballs are 2 days old. We record the location, age, band numbers, and radio frequency. We place the chicks where we found them and leave quickly. The hen is somewhere nearby, watching and waiting to return as soon as we're gone.
Prime Woods. Woodcock, along with ruffed grouse, golden-winged warblers, and many other wildlife species, thrive in young or early successional forests, which are often dominated by aspen. Young forests have dense stands of small-diameter saplings and brush, as well as open patches. This habitat mix benefits the woodcock in two ways: providing males with room for aerial displays and females shelter for nesting and raising young.
The goal of the woodcock's sky dance is to attract the ladies. The brush and short-statured trees of young forests make it easier for potential mates to admire his efforts from their spot on the edge of his singing ground.
Historically, wildfires created and maintained these young forests. Today logging, windstorms, insect outbreaks, disease, or prescribed fires set by wildlife managers can give rise to young forests. Much of the research shows that after about 10 to 15 years, these forests become less useful to woodcock and other young-forest wildlife. Some of Minnesota's forests are actually becoming too mature for these species. Carefully planned young-forest management, such as relatively frequent timber harvests, is a focus for state and federal wildlife agencies across the Great Lakes region, as well as groups such as the Ruffed Grouse Society, Woodcock Minnesota, and the Wildlife Management Institute.
That's not to say that every tree should be cut. Many wildlife species require mature forests, and we need to keep a significant amount of this habitat on the landscape. The key is striking the right pattern of young and old forests across a large landscape. The woodcock research at Tamarac should reveal what habitats those young birds are using, so we can manage for those forest types where appropriate across northern Minnesota.
Spend an evening in Minnesota's spring woods watching the flight of the woodcock and you'll never forget the experience. This delightful, odd little bird, the timberdoodle, could be at the center of a bright future for Minnesota's young forests.
Learn more about woodcock conservation at timberdoodle.org.