March 18, 2010
Thursday

Garbage allows gulls to thrive in the oilfields of northern Alaska, and furry little pikas might be changing their body shapes in response to changes in climate, according to two graduate students who recently gave public defenses of their theses at the University of Alaska Fairbanks.

Emily Weiser spent a few summers on Alaska's North Slope, studying glaucous gulls, creamy white and gray birds most people refer to as "seagulls." The birds spend their summers off the north coast of Alaska and inland up to about 100 miles.

Weiser studied gulls at Barrow, Alaska's northernmost city; at Cape Simpson, where no people live; at Alpine oil field, in the North Slope's Colville River Delta; and at Deadhorse, a town just south of Prudhoe Bay. She wanted to see if the presence of available garbage enhanced the population of glaucous gulls, which eat just about everything, including the eggs and chicks of other birds.

"Glaucous gulls are the most abundant human-subsidized predator (in the oilfield area)," Weiser said.

She teased apart pellets the gulls had coughed up to look for the presence of plastic. The birds around Deadhorse - where there is an open landfill, unlike Barrow and the Alpine oil field, where garbage is incinerated - had a huge percentage of garbage in their diets. Using those results and some statistical analysis, she concluded that birds with access to open garbage dumps seemed to be doing better than others. For instance, garbage-consuming groups of gulls experienced higher fledgling success.

Weiser mentioned a study in which researchers found that only about four out of 10 gull chicks migrate back to the same area in which they were born. Without human-related sources of food, the wayward birds might be hitting the eggs and young of other birds, such as black brant, northern pintails, arctic terns, and shorebirds.

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