June 2012

The Last Refuge

The uncertain future of Adirondack mountaintops and the songbirds that live there

Mountain Birdwatch volunteer Denis Griffin on Nun-da-go-o Ridge. Photograph by Mary Thill

It’s still dark when the alarm on Denise Griffin’s watch beeps. She turns on a headlight, unzips her sleeping bag and her tent. Already dressed, she puts on hiking boots, grabs a full day-pack, and shoulders through a thicket of broomstick balsam. When I catch up with her at 4:30 a.m., she is standing in a bare-granite clearing on Nun-da-ga-o Ridge, in the Hurricane Mountain Wilderness, with a clipboard and pencil, her face up­turned to the lightening sky.

The song of a Swainson’s thrush bubbles to the top of the birches and conifers, followed by the bird’s droplet call. Griffin listens and writes. Minutes later a white-throated sparrow with great pipes whistles long and high, Oh sweet sweet Canada Canada Canada. A resident boreal chickadee buzzes hoarsely as if to reply, Too early.

Griffin holds still, listening to a growing chorus of songbirds. She’s doing a point count, noting any bird from a list of 10 species that she hears or sees from this location. Efficient, athletic and observant, Griffin has conducted these mountaintop surveys for 10 years. She knows the song of every bird here, and she knows to dress in fleece and lightweight hiking fabrics. In the morning quiet, my Gore-Tex jacket swishes so noisily that I hesitate to swipe at a mosquito. When her watch says 20 minutes have passed, Griffin stuffs her clipboard into her pack and strides 300 yards up the trail.

By the time we reach a second predetermined survey point, there’s enough light to reveal the fresh green of the June understory: ferns, sarsaparilla, wild lily of the valley. Griffin again stands quietly, checks her watch and takes a note as a winter wren links a series of ecstatic trills. Another Swainson’s gurgles. Magnolia warblers flit and sing through the low trees. A nosy black-capped chickadee hops to our level to investigate—the first bird we’ve actually seen and not just heard. A junco’s trill rings like a phone. Griffin tilts her head, trying to pick out the tiny voice of a blackpoll warbler beyond. I wish the magnolias would pipe down; they are not on the list.

As much as 90 percent of ornithologists’ field data comes from birdwatchers. Griffin, age 50, is a registered nurse, not a scientist, but over the past decade she and dozens of other mountain-climbing volunteers have pieced together the only long-term collection of information on alpine songbird populations in the northeastern United States.

“[O]nly a freak ornithologist would think of leaving the trails for more than a few feet,” biologist George Wallace wrote in 1939 about his study of Mount Mansfield, in Vermont. Wallace himself ventured off-trail into “the discouragingly dense tangles” to study the Bicknell’s thrush, but most breeding bird surveys today are conducted along roadsides. Because the High Peaks of the Adirondacks and mountaintops of New England are so remote, windswept, and scratchy with stunted spruce and balsam, relatively little was known about the population trends of birds that nest there until recently.

Mountain Birdwatch, a program of the Vermont Center for Ecostudies, an independent research group based in White River Junction, was started in 2000 to fill gaps in knowledge about the Northeast’s high-country nesters. In addition to practicing the old-fashioned field skills of watching and listening, Griffin and 60 other volunteer naturalists undergo training so that sightings at 636 points on 116 different mountains are recorded in a uniform protocol.

As citizen scientists go, Mountain Birdwatch volunteers are an elite force. “What’s different about this [program] is that the level of commitment is greater, not so much in the amount of time but in the level of effort, the intensity of effort, that’s required,” says Chris Rimmer, a biologist who has studied mountain songbirds for 20 years with the Vermont Center for Ecostudies. “We’re asking people to do dawn counts on mountaintops. Weather conditions can be harsh, blackflies can be voracious…. It requires a lot of dedication and commitment.”

The study area is bordered on the west by Loon Lake Mountain in Franklin County, one of 19 peaks surveyed in the Adirondacks, and on the south by Slide Mountain in the Catskills. The survey stretches northeast across the tops of the Green and White Mountains to Mount Katahdin, in Maine. In June, during a brief few weeks when migratory songbirds make themselves conspicuous by singing to define breeding territory, birders hike above elevations of 3,000 feet in the dark, or like Griffin they camp near treeline the night before their survey. In the weeks preceding her count, Griffin twice made the 900-foot ascent of Keene’s Nun-da-ga-o Ridge to scout her five assigned points. Mountain Birdwatch technicians had marked the sites the previous season with discreet metal tags nailed to weathered trees.

The scientific rigor of data collection is giving conservation biologists a foundation to measure variables that could be depleting populations of high-elevation songbirds—among them acid rain, methylmercury, climate change and winter habitat loss. Of the 10 species surveyed, half are in decline.

Mountain Birdwatch volunteers listen for black-capped chickadee, hermit thrush, Swainson’s thrush, white-throated sparrow and winter wren—birds that also make themselves heard in Adi­rondack lowlands. The birdwatchers study audio CDs to familiarize themselves with songs and calls of more-specialized boreal nesters: blackpoll warbler, boreal chickadee, yellow-bellied flycatcher and fox sparrow (the latter is a Canadian summer resident occasionally found in Maine, rarely in the Adirondacks). But it was Bicknell’s thrush—a seldom-seen, mousy-colored bird almost exclusive to the region—that got the study going.

At the fifth and final survey point, Griffin notes the time— 6:40 a.m.—and takes a compass bearing. She’s encircled by balsams draped with gray-green usnea lichen, a gnarled northern epiphyte sometimes called old man’s beard. She ignores mosquitoes and an insistent ovenbird’s tea-cher tea-cher TEA-CHER, raising an index finger instead at a quick che-bek. She writes YBFL on her clipboard—shorthand for yellow-bellied flycatcher, a summer resident of cool conifer forests and peatlands.

She ignores a red-breasted nuthatch, a yellow-rumped warbler, a black-throated blue warbler and wrist-biting blackflies. A boreal chickadee perches eight feet above her head, and then—for a moment—nothing stirs. A sudden quiet takes hold. Hyper-alert to sound for two hours now, I realize we haven’t heard silence since first light. A distant jet fills the void, and then a Swainson’s sings to the west. Matins resume.

At 7:01 a.m. Griffin is done counting birds, and we make noise. I unzip my pack and lift my head net to drink tepid thermos coffee. Griffin goes light with just bug dope and chocolate-covered espresso beans. The blackflies are thick but thankfully aimless. After a break Griffin raises her binoculars and begins to count cones on red spruces and balsam firs. Biologists have detected a correlation between the number of conifer cones and the success of songbird reproduction. Red squirrels are the main predator of high-elevation nests, and cones are a staple of the squirrels’ diet. In autumn after a big cone crop, such as 2011’s, red squirrels migrate up mountainsides. This spring and summer the rodents are expected to feast on the eggs and nestlings of returning birds.

Griffin calls my attention to a thin, insectlike tsi tsi tsi tsi tsi tsi tsi tsi tsi. A blackpoll warbler. The little black-capped passerine makes one of the longest overwater flights of any bird: after summering in the boreal forest, it hops out over the Atlantic and flies nonstop up to 88 hours and 2,000 miles to its winter grounds in Puerto Rico or South America. No heroics today: the blackpoll stays hidden in the understory. In the Adirondacks, they are strictly mountain creatures, usually nesting above 3,500 feet. The Second Atlas of Breeding Birds in New York State (2008) calls them “inadequately monitored.” Populations appear to be declining significantly across the Northeast, but counts so far are not de­tailed enough to be conclusive.

On this morning we never hear the nasal, fluty fall-and-rise of a Bicknell’s thrush. Nun-da-ga-o is only 3,100 feet high, perhaps not ideal for a cold-tolerant bird more often found in krummholz, near 4,000 feet. But Griffin recalls a year on Mc­Kenzie Mountain when a thrush perched on a snag 20 feet from her and sang as she sat and watched. Brian McAllister, who founded the Adirondack Birding Center at the Paul Smiths Visitor Interpretive Center, once guided me to a Bicknell’s that also tarried and performed on Hurricane Mountain. The bird’s trophy status derives not so much from shyness as from rarity, the difficulty of distinguishing it from other thrushes, the density and inaccessibility of its habitat, and the very limited quantity of that habitat.

“It was great just to see one,” recalls Adam Welz, a South Af­rican now living in Brooklyn who has 1,538 birds on his life list. He and a group of birders saw a Bicknell’s last June near the summit of Whiteface Mountain, the only Adirondack High Peak accessible by road. It took more than an hour of looking. “We drove to the top. There was a footrace that day, and a tortured procession of runners was coming to the end of their jog and wondering what we were doing just staring out in­to nowhere.”

The Adirondacks and New Hampshire’s White Mountains are the Bicknell’s motherlode, Chris Rimmer says. Joan Collins, a professional birdwatching guide who runs Adirondack Avian Expeditions in Hamilton County, tells me birders from around the world travel to the Adirondacks to add Bicknell’s thrush to their lists. “It’s the bird that brings people to our area,” she says.  Collins is also a Mountain Birdwatch volunteer. “I watched Bicknell’s disappear on Kempshall Mountain,” she says. “I found them there for three years in a row and then [around 2004] they were gone.” On the shore of Long Lake and 3,350 feet high, Kempshall is low and southerly relative to the bird’s core breeding range. Collins suspects that warming temperatures may be narrowing the bird’s already condensed territory.

The International Union for the Conservation of Nature classifies one in eight bird species as threatened with extinction, Bicknell’s thrush among them. In an age of rapid, systemic environmental change, it might seem antiquated to send people hiking to count a bird song by song. But data about a bird can also tell us about the health of the larger ecosystem, says Judith Scarl, coordinator of the Mountain Birdwatch study.

In the Northeast, montane spruce-fir forest covers less than one percent of the landscape but makes a major contribution to avian diversity. A 1990s New Hampshire study documented annual Bicknell’s population declines of seven percent. Preliminary Mountain Birdwatch data are more hopeful, tentatively indicating an increase in sightings throughout the Northeast; last year, Bicknell’s thrush was detected at 183 (about 30 percent) of randomly selected survey points, Scarl reports. Biologists caution that many more years’ data are necessary before they can get a handle on trends. So, volunteers will climb and count in­definitely. It’s estimated that more than 90 percent of Bicknell’s thrushes nest in the Northeast. Outside the United States they breed only in the adjacent boreal highlands of Quebec, New Brunswick and Nova Scotia. Canadian studies are tracking what appear to be much steeper annual population decreases of 15 percent and greater.

It’s not really known how many Bicknell’s thrushes exist: Chris Rimmer ballparks the global population at 100,000. What is known is that the species has a more-restricted summer and winter range than any North American bird, and both places are under stress. Bicknell’s thrush winters mainly in the Dominican Republic, on the highest mountains in the Caribbean, which have been deforested by farming, logging and ranching to 10 percent of their original tropical lushness.

In the Northeast and Canada, acid rain from coal-fired Midwestern power plants has leached calcium from forest soils, killing high-altitude red spruce and threatening to weaken eggshells. Airborne mercury from the same sources is manifest in elevated levels of toxic methylmercury in mountain birds’ tissues. There has been some good news: power-plant emissions are gradually being made cleaner, and scientists have all but eliminated ski resorts from the list of threats to Bicknell’s summer habitat; a Vermont study found nests to be more abundant near ski trails and natural clearings than in deep woods. Logging is not an issue on most northeastern United States mountains, which are preserved or inaccessible to skidders. But industrial forestry appears to be causing the bird’s decline in heavily timbered parts of Canada.

Climate change is the range-wide danger. “Even at two de­grees change, we’re looking at losing the majority of the [summer] habitat,” Judith Scarl says. And almost all climate models predict the temperature will rise more than two degrees this century. Some scientists think hardwoods might displace spruce and fir on high mountainsides. Or introduced pests such as balsam woolly adelgid may kill trees when winters are no longer cold enough to keep the bugs at bay. There is speculation that Swainson’s thrush, whose distribution overlaps the lower reaches of Bicknell’s, may claim its niche, though there’s scant evidence that the species currently compete.

The future effect of warming on Northeastern birds defies prediction. There will be surprises. Birds respond flexibly to changes in weather and other obstacles during migration, but how they respond to loss of nesting grounds may depend on how rapidly the habitat changes. Some species may be adaptable—generalists like crows are famously so—but specialists like Bicknell’s are most at risk.

Mountaintops are poetically described as “sky islands,” an image that helps illustrate why they’re among the most vulnerable habitat in the Northeast. “You definitely get the impression of these birds being confined on this peak, surrounded by a kind of rising water of climate shift,” Adam Welz observed after his sighting on Whiteface.

After counting birds and cones, Griffin seems more exhilarated than exhausted, even though she got only about four hours’ sleep and worked a 12-hour shift in Lake Placid’s emergency room before hiking in the previous night. On the walk down off the ridge she takes time to identify violets, to splash her face in a clear stream, to enjoy being in the woods.

“This is just one way of giving back that’s really fun,” she reflected later. “I mean, I’m selfish. I am doing something that is hopefully making some kind of contribution, but at the same time it’s an amazing experience. I love being out there.” In June 2012 she will repeat her point surveys on Nun-da-ga-o, and she’s adding Saddleback Mountain, a higher peak where she has a better chance of seeing a Bicknell’s.

There are other efforts aimed at helping the Northeast’s mountain birds. The International Bicknell’s Thrush Conservation Group set a goal of increasing the bird’s population by 25 percent over the next 50 years. Others are trying to get the thrush listed as endangered, though the Endangered Species Act currently has no influence on climate policy. Chris Rimmer, meanwhile, has immediate, ground-level concerns. He is hoping to build up the Bicknell’s Thrush Protection Fund, established at the Adirondack Community Trust, to strengthen conservation efforts in the Dominican Republic, where de­forestation continues.

“We think of these as our birds, because they’re nesting and procreating here, but they’re only here three or four months, and they’re spending most of their life somewhere else,” he says. “The island of Hispaniola has 31 species of birds which are found nowhere else on the planet. Many of them share the same habitat as Bicknell’s thrush.… By doing a good job of protecting Bicknell’s, we protect a whole suite of biodiversity and birds that are quite precious and rare. It’s about much more than Bicknell’s thrush down there—and up here. It’s the mountaintops. These mountains are our treasured resource, an iconic part of the landscape. Bicknell’s thrush is the only bird that lives in these mountains and no other habitat in the United States.”

In Search of Bicknell’s Thrush
When: The earlier in the morning the better. They sing throughout June and early July. You’re more likely to hear one than see one.
Mountainside forest above 3,500 feet. If you prefer driving to hiking, Whiteface Mountain Veterans Memorial Highway, in Wilmington, is the place to go:

Tags: , , , , , , , , , , ,