Paddling deep into the forest, Jeff Wells, senior scientist with the Boreal Songbird Initiative, and I plan to survey for breeding birds and record bird choruses in the height of summer mating season at stops along the way. Even though an average of 30 million to 50 million birds fly south over the U.S.–Canada border every night during fall migration, scientists have few specifics about the way they spend their time on these breeding grounds. Wells will archive our data and these oral histories of the boreal wilds at Cornell University’s Macauley Library of Natural Sounds, one of the world’s largest such collections. In fact, they’ll be the library’s very first acoustic samples from this section of Ontario’s Albany River.
Thankfully, the storm clouds clear nearly as quickly as they appeared, leaving us just enough time to throw up a tent in a knuckle of beaver-gnawed woods. The day has been a rough start, hurried and unsettled. Now common loons sound their haunting cries over the water. As I lie in my sleeping bag, I imagine millions of boreal birds, tucked into nests, unseen and unheard in the wilderness around me. They are gathering their strength, I suspect. They will need it, for here in the boreal, the breeding frenzy is on.
Sunrise comes early to the boreal dawn. I wake to tent walls glowing orange in the early light and humming with the sound of mosquitoes swarming against the thin fabric. My watch reads 4:20 a.m.
A half-hour later we clamber atop a beaver lodge a few hundred yards from camp. I slip on a set of stereo headphones hooked up to a digital field recorder, and the morning’s spring chorus turns into a kaleidoscopic fusion of sound. A Wilson’s warbler chatters from the woods. A ruby-crowned kinglet whistles a slurred opening trill. What I’m hearing is the auditory version of going from a black-and-white TV to an IMAX film. I hear a swamp sparrow as if the bird is clinging to my hat brim. The croak of a female goldeneye. The hammer-tap of yellow-bellied sapsuckers. The trill and buzz of a northern waterthrush, an alder flycatcher, a blue-headed vireo, a winter wren. Suddenly a song comes into sharp auditory focus: the mechanical tst tst tst teepit teepit ti-ti-ti, of a Tennessee warbler, a munchkin with a jackhammer.
Beside me, Wells’s grin says, “Gotcha!” He holds a large microphone that allows him to pinpoint the exact location of a calling bird, so the recorder slung around his neck can catch the cleanest sound possible.
After a five-minute recording session, Wells drops the microphone into his lap and scratches his mosquito-ravaged neck. “It’s amazing to be able to document the acoustic environment of such a pristine place,” he says. “It’s so difficult to get in here that scientists have very little information about the birds in these forests.” In years to come, he suggests, our recordings could be used to study changes in bird ranges or to tease apart how vocal variations differ across a species’ range.
These recordings are doubly important because the southern boreal forest, most of it slated for logging, has a much higher diversity of birds and other wildlife than the northern boreal, which is now partially protected, and many species are specifically tied to these woodlands. Bay-breasted warblers, evening grosbeaks, and black-throated green warblers pour out of Canada early each autumn, and the bulk of their breeding range is in the southern boreal forest. “We can’t just set aside the northern boreal and trash the rest,” Wells says. “That’s a recipe for disaster.”
One of the ingredients that will help thwart disaster in the boreal forests is new information about boreal breeding birds being gleaned from National Audubon Society Christmas Bird Count (CBC) data. Audubon scientists are using new statistical tools to analyze CBC counts in order to learn about the health of bird species that winter in the United States but breed so far north that they are largely absent from the roadside-oriented Breeding Bird Survey, the only other continent-wide bird population survey. All told, Audubon “citizen-scientists” have amassed five billion bird-sighting records through the CBC since 1900, but for decades the data have been underused. “These new tools are a huge advancement,” says Daniel Nivens, a senior Audubon scientist. “We didn’t have reliable continent-wide quantitative data on perhaps 100 boreal bird species, such as Harris’s sparrows, rusty blackbirds, and common redpolls. Now we’ve put together a more complete picture of what’s happening with some of these boreal breeding birds, and that will help us understand how they are responding to both changes in habitat and climate. It’s exciting to think that it’s all because of 50,000 birders who are passionate about counting birds.”
A few hours later birdsong reveries seem a distant memory. Our first major portage is a monster. A narrow, muddy route that bypasses nasty rapids above Kawitos Lake, it is choked with blowdowns and barely passable. We bushwhack a route across a trio of beaver dams, but it peters out into alder-choked boulder fields. Hand over hand, pushing and shoving, Wells and I drag the loaded canoe over a half-mile of rocky channel until there is hardly any water at all.