Forty years of change on top of the world
From a lecture hall within a land of warm breezes and flowering December plants comes a story of a creature 2,600 miles north, where the sun will not rise for another 50 days.
At the 2012 Fall Meeting of the American Geophysical Union, biologist George Divoky had 15 minutes to present his lifetime of work with a bird that adapted to year-round life in the Arctic during the last ice age. Divoky led off a lecture session on Barrow-area research by describing his four decades of studying birds that probably would not exist without his efforts — the black guillemots of Cooper Island, Alaska.
In the early 1970s, the biologist found a small colony of the birds on a gravel island in the Beaufort Sea about 25 miles northwest of Barrow. Black guillemots were breeding in nest cavities in wood debris left by the U.S. Navy in the 1950s. Divoky created more nests by rearranging other pieces of wood. The black guillemots, sleek birds that spend their entire lives in the Arctic, used his improvised nest boxes to lay eggs and raise chicks. The birds prospered.
Divoky became so enamored with the island and the birds that he has returned there using intermittent and varied funding sources each summer since 1975. In those 37 years, his study has evolved from the biology of an intriguing species to a straightforward tale of climate change. The latter made him the subject of a 13,000-word story in the New York Times Magazine in 2002 and landed him a seat next to David Letterman on the late-night talk show in Manhattan.
The story goes something like this: while Divoky was measuring eggs and placing bands on the legs of black guillemots with cold fingers in the 1970s, 1980s and 1990s, the far north was changing faster than anywhere else in the world. Summer is now one month longer than when Divoky started his study, and Barrow has warmed by 3 degrees centigrade. This warmth, and the melting of snow and shrinking of sea ice that came with it, profoundly affected his birds.
Black guillemots, which also nest in other far-north places in natural rock cavities, prefer to feed their nestlings arctic cod that live in cold waters at the edge of sea ice. Divoky calculated that parent birds can fly a maximum of about 18 miles from Cooper Island to the ice edge and still have the energy to return and drop a fatty cod at the nest. With the ice close to the island in the 1970s, ‘80s and ‘90s, parent birds were able to bring home cod, but in recent years, the ice pack has shrunk toward the pole. In recent years, the ice edge has been hundreds of miles from Cooper Island during the birds’ August feeding time.
Parent birds now feed their chicks sculpin and other species less energy-rich than the cod. Divoky has watched nestling success plummet due to the shrinking sea ice, just as he watched them succeed as the ice freed up Cooper Island in the early 1970s.
“The western Arctic has gone from being too cold to being too warm for guillemots in approximately four decades,” Divoky said.
Lack of summer sea ice is not the birds’ only challenge. After Divoky had seen just two polar bears from a distance in all his years of study, in 2002 the bears began occupying Cooper Island as a refuge in a world without ice visible on the horizon. The bears sniffed out and ate guillemot chicks.
In the following years, subarctic horned puffins expanded their range northward to the island. Finding the nest boxes attractive, they destroyed eggs and killed guillemot chicks to make the cavities their own. In 2009, 200 chicks hatched; polar bears ate 90 of them and puffins killed 80. Only one guillemot chick fledged that year.
Divoky brainstormed on what he could do to save the colony that was so valuable in terms of observing an animal’s adaptations to change. He came up with the solution of making nest boxes out of shock-proof plastic camera cases. In summer 2011, he replaced the wooden boxes with a scattering of the plastic cases. The birds nested in them. The puffins and the bears couldn’t get in. The black guillemot colony is recovering.
“Guillemots are surviving on Cooper Island, but they’re living in bunkers,” Divoky said.
Divoky returns to Cooper Island for 13 weeks each summer. Because of the polar bears, he now stays in a small cabin he has built there, rather than the tent he had used for decades. An electric fence surrounds the cabin. He has attached tracking devices to the birds and has found they spend winters in the Bering Sea.
These days, he sees his birds telling yet another story of the far north — the black guillemots can be indicators of the health of an ecosystem threatened by the inevitable development by the oil and gas industry. If there was an oil spill, for example, Divoky and his helpers would know how many birds did not return the next breeding season.
“This is the only seabird colony all the way east to Canada, and all these birds come back (to Cooper Island) to breed,” he said. “We know every year what survives.”
Divoky, who formed the nonprofit Friends of Cooper Island (cooperisland.org) when people worldwide began sending donations following the New York Times story, will return next summer to his guillemots, some of which he has known since he crimped metal bands around their legs 30 years ago. The man who was the subject of a climate change play on England’s Royal National Theatre and who once helicoptered off the island in mid-summer to attend the high-powered Aspen Environment Forum will once again be sleeping on a windy island during the bleak arctic summer. His knees chilled as he kneels on cold gravel, he will measure eggs to the nearest millimeter, weigh squeaking chicks by hand, and pause now and then to raise his head and squint through the fog for polar bears.
Since the late 1970s, the University of Alaska Fairbanks’ Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute.