Few birds winter in the Arctic because of the harsh climate conditions. But in the spring, there is a veritable explosion as millions of birds return to nest. Seabirds in Mallory's study area tend to spend the winter months floating in the North Atlantic ocean. When they return in the spring, conditions are often still very harsh. Mallory has seen fulmars and thick-billed murres incubate eggs with only their heads visible above the snow.
The preferred nesting sites of many seabirds are cliffs, which often prove to be very dangerous. Falling rocks and chunks of ice, as well as slides kill great numbers of birds. In fact, the authors cite one incident in which over 800 murres and kittiwakes died almost instantly when the ledges on which they were nesting collapsed. Mallory suspects cliffs could become unstable as temperatures rise, with more freeze-thaw action of ice.
And not all cliffs provide a safe haven from predators. Cliff-dwelling birds are, of course, easily accessible by other predatory birds. But Arctic foxes and even polar bears have been observed on cliff sides eating eggs, chicks or adult nesting birds.
"It's always shocking to see a polar bear on a cliff," says Mallory adding, "I saw Arctic foxes down what appeared to be effectively a vertical wall. And the Inuit report seeing more polar bears on cliffs. So these birds think they are safe, but they are not."
The Arctic has been getting warmer and increased temperatures create stronger storm fronts and bring more precipitation to what is essentially a desert region. For birds adapted to a cold, dry climate, these changes could be very challenging.
"Arctic seabirds don't do well in really heavy, wet snowfall. Chicks hatch in early August and they expect it to be dry and cool. They can't handle soa
|Contact: Ruth Klinkhammer|
Arctic Institute of North America