Climate Change Helps Wandering Albatrosses Fly Faster
One species is actually benefitting from climate change, at least for now. Faster wind speeds in the Southern Ocean are allowing the wandering albatross—one of the world’s largest birds, with an impressive 11-foot wingspan—to fly faster between its breeding grounds on the Crozet Islands and foraging grounds at sea. That’s resulted in better breeding success, and bigger birds: they weigh 2.2 pounds more on average now than 20 years ago (about a 10% increase in body mass).
“People generally see climate changes having obligatorily negative effects on populations and species of animals and plants,” says Henri Weimerskirch, of France’s Centre d’Etudes Biologiques de Chizé, who reports the findings in the January 13 issue of Science. With wandering albatrosses “this is obviously not the case.”
Researchers have been studying the Crozet Island population since 1966, and tracking the birds’ movements with transmitters since 1989. As westerly winds in the Southern Ocean have increased in intensity and moved poleward, likely due to climate change, albatrosses have followed.
“In the 2000s, birds moved quicker than in the 1990s and thus were able to cover similar distances during shorter bouts at sea,” the authors write in the paper.
Because this allows them to spend less time at sea while incubating eggs, they’ve had better breeding success over the past decade. Females, in particular, are foraging for squid and fish in more southward and windy areas—a shift that may have the added benefit of moving the birds out of the subtropical waters where long-line fishermen hunt for tuna. Longline fishing, which involves trailing lines with baited hooks behind boats, is the main threat to the species. Albatrosses get tangled up when they go after the bait.
The shifting winds are likely affecting other seabirds, too. “Other petrels and albatrosses are also using wind as a source of energy for their flight, so undoubtedly these changes in wind patterns might have affected also other species, but we have no long-term data on other species,” says Weimerskirch. “Increase in wind speed over oceanic waters is a general pattern worldwide, and this should for example also affect the migration patterns of trans-hemispheric migratory shearwaters, that are known to use wind conditions for their movements.”
While a boon to wandering albatrosses now, the positive effects may not last if climate warming continues. Models predict that westerly winds will continue to move poleward and increase in intensity. The winds may become too strong for dynamic soaring flights, which allows albatrosses to conserve energy by not flapping, and ultimately foraging may become much more costly. Other albatrosses and petrels may end up in the same boat, the researchers warn.
The most surprising find to Weimerskirch was the increase in body weight over such a short period of time. It’s likely in part due to shorter fasts on the nest while the albatross waits for its partner to return and take over, but it might also be an adaptive response to the windier conditions, as body mass affects flight performance. Says Weimerskirch, “This is a considerable increase and completely unexpected.”