I am standing on the shores of Timber Lake, a frigid tarn in Alaska’s Brooks Range. I and my team are camped here for two weeks to record the soundscape of the Arctic National Wildlife Refuge.
Two other crews are stationed at sites further north in the Refuge. Our goal is to capture the creature voices — “biophony” — using sound to complement more conventional forms of scientific survey methods that rely strictly on visual cues. The sounds will document the density and diversity of species inhabiting this wild open country. Perhaps too, they will provide a baseline for future comparison. For life here in this isolated region is undergoing change.
On the island in the middle of Timber Lake three pairs of Arctic tern, Sterna paradisaea, are preparing to nest. Their courtship flights are a marvelous display of aerial acrobatics and sweet deference. Our sensitive microphones, tuned to the subtleties of distant, ambient sounds, peak with the terns’ shrieking Keeer! Keer! warning us to stay away. The Yupik Eskimo people name this bird after its fierce defense of territory: “little bird that deposits on your head as it flies over.”
Arctic terns arrive in Maine in the early summer, swooping and diving over the chill North Atlantic. An Arctic tern in flight is an expression of perfection: floating on raked wings, its flight appears to be pure, effortless grace. As if born on the wing, they perform aerial acrobatics seemingly out of the sheer joy of flight.
That is a purely human construct, for the Arctic tern is all business, a wild creature perfectly adapted to life on the wing. They are the world’s migration champions, flying every year from their arctic breeding grounds south to Antarctica. It is a round trip flight of up to 31,000 miles a year.
What drives this creature to make such heroic journeys year after year to endless daylight? Fear of the dark? Doubtful. Likely, Arctic terns keep on the go in search of food to fuel their constant peregrinations, and to nurture their young. Timing of migration to their northern summer breeding grounds and austral summer grounds is tuned to the rhythms of seasonally abundant food supply.
Not much food appears to be available in early June here in the Brooks Range. Temperatures have dipped into the single numbers under the assault of a Siberian cold front. Timber Lake’s ice grows and ebbs, but is gradually yielding to summer’s intense sun. Mid June will find this place humming with insects. Fish and birds will feast.
Two forces compel us to undertake the rigors of arctic research. The first and most obvious is the potential opening of the Refuge to industrial oil and gas leasing by the federal government. Along a 100-mile stretch of coastline where the Brooks Range and the Arctic Sea converge, the coastal plain narrows. There, for a few months, life ramps up, and all creatures heed a biological call to calve, hatch or spawn. No one can predict what impact oil and gas exploration will have on the natural rhythms that have played out here for millennia undisturbed by human intervention. Certainly the balance will shift with the introduction of roads, construction machinery, lights and air traffic. A hydrophone (literally a “water microphone”) placed in the Arctic Sea picks up the sound of undersea drilling over 60 miles to the west. Our human footprint is not subtle.
The second threat to the Refuge is less focused, more insidious. It is the gradual warming of the Arctic climate. While earth’s average atmospheric temperature has risen 1°F since the industrial revolution, warming in the arctic is happening at twice that rate. Summer pack ice, where polar bears roam in search of prey, is up to 90 miles from shore; a polar bear can swim 50 or 60 miles before exhaustion. Summer is coming earlier. Insects and fish will hatch long before their counterparts in temperate climes.
Which brings us back to the Arctic tern. They arrive here on their own timetable set by wind, weather and available food along their 15,000-mile northward journey. How fragile is the link between breeding grounds and wintering grounds? What happens if the timing of their food supply shifts ever so slightly earlier? Can the Arctic tern adapt?
On the shore of Timber Lake, I ponder whether the vocalizations I am hearing here are the sounds of enduring life, or destined for an archive. Can we acknowledge the pressures of global warming and change our habits and lead by example? Let’s hope we can, before the Arctic Tern and other species are pushed beyond their limits.