Sunday, January 16

Global warming causes an increase in “divorces” … among albatrosses

Known as one of the most faithfully monogamous species, albatrosses are increasingly separating themselves. A Royal Society study attributes this behavior, unusual for these birds, to global warming. The warmer waters and therefore less fish force them to extend their hunting perimeter, making their life more difficult.

Researchers from the Royal Society have studied a wild population of 15,500 breeding pairs of black-browed albatrosses in the Falkland Islands for 15 years. So far, figures have shown only 1 to 3% of separations in these birds. But, according to this new research, this figure has steadily increased in recent years, reaching 8%.

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However, the fact of finding less fish, due to the warming of the waters, could lead to more failed matings, suggests the scientist. Albatrosses would separate more because they have a harder time giving birth and surviving their chicks. But that’s not all, because the researchers also observed separations among couples who did not have difficulty reproducing.

Francesco Ventura then evokes a more direct effect of the rising water temperature. Since birds are forced to hunt longer and fly further for food, then it is possible that they will not return in time for a breeding season and their partner will choose another mate. Beyond that, the stress generated by these new difficulties could be enough to disturb the harmony of the couple.

Populations reduced by 5 to 10% each year

The phenomenon is worrying according to Graeme Elliot, senior science adviser at the New Zealand Department of Conservation. He evokes populations of albatrosses in great difficulty and whose number is “in free fall”. Certain groups, notably the Wandering Albatrosses, which he studies, have reduced by 5 to 10% each year since 2005. Not only do they lack prey but they are also more and more often accidentally killed by the lines or the boats of peach.

This decrease in the number of individuals also contributes to the modification of the mating patterns of birds. Thus, Graeme Elliot saw the appearance of a greater number of homosexual couples, in particular males, on the Antipodes Islands (New Zealand). “A certain percentage of young males associate with each other because they cannot find a female partner,” he explains.

Since the albatross population observed by researchers from the Royal Society in the Falkland Islands is substantial, the increase in separations has not, for the time being, really been a problem: the birds could always find another partner. . But scientists fear that this dynamic will spread to smaller populations, where reproductive processes could be permanently disrupted. Knowing that the number of individuals is already on the decline, Graeme Elliot sounds the alarm: “If we do not reverse the trend, they will die out.”

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