Ice provides a hard substrate that allows seabirds to leave the water to roost. This allows such species as the Larus gulls, which typically roost on hard substrates, to occur in large numbers well offshore.
Sea Ice Reduces Wind Chill
The unevenness of the upper surface of the ice reduces the speed of winds directly over the ice, thus providing a microhabitat and reducing the amount of wind chill for birds sitting on and next to the ice.
Sea Ice Decreases Wave Action
Ice floating on the water reduces the surface disturbance of the water. Although swells pass through areas with much ice cover, waves do not. In addition, surface waters on the lee side of ice floes and cakes usually have little surface disturbance. Surface feeders may be able to locate prey more easily because of these reductions in surface disturbance.
Specific Effects of Ice on Birds in the Western Arctic
The retreat of the pack ice each spring and the formation of new ice each fall greatly affect a large area of the Arctic Ocean off the coast of Alaska and much of the Bering Sea. Specific ways in which birds are affected by ice in the western Arctic are discussed on a seasonal basis. All observations are my own, unless otherwise stated.