A Thwack in the Park

American woodcock, golden-winged warbler, and New England cottontail are sometimes called "guild species" or "umbrella species," because the habitat they require -- shrubland, brushland, early successional habitat, sometimes summed up as young forest -- provides food and cover for so many other kinds of wildlife.

By Marilyn Kitchell, biologist, Great Swamp National Wildlife Refuge, Morris County, NJ

I spent the fall of 2017 and winter of 2018 thwacking my way through the refuge’s brushy young forests. Blackberry brambles snagging my thick Carhartt coveralls and grabbing my every limb made progress slow. Gnarly stumps lay their own obstacle course at my feet. Ducking below and around bare thin branches, I tried to spare my rosy red cheeks and face from the poking and scratching that threatened the only parts of me exposed in the cold, crisp air.

American woodcock

Woodcock feeding on earthworms in moist soil./T. Flanigan

My task: evaluate each field and determine its fate – would it be cut this year, or would it remain?

No wonder the woodcock love this stuff, I thought. This is a miserable place to be a large mammal. Opposable thumbs aside, I can’t imagine it’s much easier for a fox or a coyote to make its way through here.

I envision what it must be like for a woodcock to wander through this brush, navigating their way through stems spaced like agility pegs and horse jumps. A canopy of branches is layered above. Dense leaves hide the sky from the woodcock’s upward-looking and predator-leery eyes. The moist earth, protected from the sun’s evaporative rays by leaves above and underfoot, is chock full of earthworms who erroneously think THEY are protected by all the brambles.

Not to be outsmarted, the woodcock have developed a graceful dance – a sort of forward-stepping, vertical bobbing motion – to detect the earthworm’s nearly imperceptible underground presence. Shielded by all that’s above, the woodcock must feel that this is the perfect place to build their ground nests and raise their fluffy young.

So if these brushy fields are so good for woodcock, you might ask: Why was it my task to evaluate them for possible cutting? To answer that, we turn to the U.S Fish and Wildlife Service’s Migratory Birds program, and the annual surveys that they’ve been conducting – one that the refuge participates in annually – since 1968.

Each spring, states and National Wildlife Refuges alike send volunteers and staff out to listen for singing males on 1,000 woodcock survey routes across the species’ range. Following a standardized protocol, this cooperative data is submitted annually to the Service’s Division of Migratory Bird Management at Patuxent Research Refuge in Laurel, Maryland. Once compiled, the data is used to monitor the rangewide population and then to set annual hunting harvest limits at the federal level. This longterm dataset shows that the woodcock population has been in steady decline since surveys began. And the primary reason for their decline? The loss of the habitat they need for feeding, hiding out, and raising young.

graph of woodcock population trend

Average number of woodcock heard on annual survey routes across the Eastern region, 1968-2018./Graph from Seamans and Rau 2018, American Woodcock Population Status, 2018. USFWS, Laurel, MD)

You see, woodcock depend on brushlands and thickets (sometimes called young forest) for siting their nests on the ground and then rearing their young. The protection this dense habitat offers from mammalian and avian predators, and the rich earthworms that can be found there, make it prime real estate for timberdoodles.

But brushlands themselves are a short-lived phenomenon, and around the Great Swamp Refuge they can attain forest character (with trees dominating and shading out the vegetation at ground level) in as few as 10 years. Across the East, since the 1960s, nearly 13 million acres of scrubby brushland habitats have been lost either to suburban development or to their conversion to older forest – and with it go the woodcock.

Throughout the Northeast, mature forests seem to have captured the heart of the average suburbanite as the sign of a healthy bit of nature left to be – and scrubby brush can be perceived as an interim mess, no longer pretty or useful (at least to us). Beauty is, of course, in the eye of the beholder. For the woodcock, the loss of brushlands has been an ugly thing.

And so, odd as it sounds, the only way to maintain these ephemeral habitats is . . . to cut them down. By cutting early successional (“young”) habitats in rotation, staggered from year to year and field by field, the refuge is able to consistently maintain suitable habitat for our woodcock friends. And as much as our brushlands love to grow up into forest, they are equally eager to regenerate (grow back) after cutting – often coming back even thicker than they started. In as little as six months, those fields will be dense with vegetation five to six feet tall, eagerly sprouting upward and outward.

And the woodcock happen to love hanging out in those really thick brushlands, even if I do not.