Global warming causes albatross’ divorce rate to rise
More than 90% of birds are monogamous, and most of them are loyal to their partners. Among them, the albatross is a typical representative. Couples of albatross rarely separate and stay with the same partner year after year. However, a new study published in the Proceedings of the Royal Society, Series B recently found that the "divorce rate" of albatross has risen, and global warming may be the culprit.
This time, in order to find out whether the environment has a direct impact on the "divorce rate" of albatross, the researchers analyzed the reproduction of 15,500 pairs of wild black-browed albatross living on the Frank Islands from 2004 to 2019. They found that in the early "marriage life" stage of albatross, reproduction failure was still the main factor of "divorce". Those albatrosses who did not successfully hatch their chicks were more than five times more likely to be separated from their partners than those who successfully hatched their chicks.
According to the researchers, in the years when the seawater temperature was relatively high, the "divorce rate" of albatross in the Falkland Islands in the South Atlantic increased from an average of less than 4% to nearly 8%. This is the first time there is evidence that environmental factors affect the "marriage" of wild birds, not just the cause of reproduction failure.
Francisco Ventura, a conservationist at the University of Lisbon in Portugal, puts forward two possible reasons: one is that warmer seas force birds to hunt longer and fly farther. If the birds fail to return during the breeding season, their partners may look for "new people." Second, when the water temperature rises and the environment become worse, the stress hormones of the albatross rise, which will affect the choice of mates.
Researchers believe that this result shows that the "divorce rate" of albatross and other monogamous animals is higher due to climate change caused by human activities.
Albatross can live for decades, sometimes spending years in the ocean searching for food, and then returning to land to reproduce. Being with your partner helps to raise their children. Ventura said that this kind of stability is particularly important in a dynamic marine environment.
If reproduction is unsuccessful, many birds, mainly females, will leave their mates and look for a better "future" elsewhere. In years when conditions are more difficult, bird reproduction is more likely to fail and have a knock-on effect on the "divorce rate" in the following years.