Winds off the Southern Ocean, around Antarctica, are shifting, making it easier for a particular species of albatross to fly farther.
One species, the wandering albatross, can fly more than 2,175 miles (3,500 kilometers) looking for food, particularly dead squid floating on the ocean. During the summer, one breeding partner can travel for days or weeks at a time in search of food while the other incubates the egg.
Over the last two decades and possibly longer, changes in winds appear to have led to shorter, easier foraging trips, leading to heavier birds and more chicks for a population of wandering albatrosses on Possession Island, one of the Crozet Islands in the Southern Ocean, according to a study published in the Jan. 13 issue of the journal Science.
Winds of change
Over the past 50 years, summertime westerly winds over the mid-latitudes, within which Possession Island lies, have been shifting farther south, closer to the Pole, and strengthening.
The hole in the protective ozone layer — which has expanded above the Antarctic during recent decades but is expected to recover eventually — is primarily responsible. The ozone hole decreases temperatures above the Pole. This creates a more significant atmospheric pressure difference between the polar region and the tropics, resulting in a shift and strengthening of the westerly winds, according to Judith Perlwitz, a research scientist at the University of Colorado, Boulder, who was not involved in the study.