Why did nearly a million king penguins vanish without a trace?

[NNadir]

Last edited Sat Mar 21, 2020, 08:07 AM - Edit history (2)

A news item from Science, I think it's open sourced: Why did nearly a million king penguins vanish without a trace?

In case it's not open sourced, some excerpts:

Where on Earth, wondered Henri Weimerskirch, were all the penguins? It was early 2017. Colleagues had sent the seabird ecologist aerial photos of Île aux Cochons, a barren volcanic island halfway between Madagascar and Antarctica that humans rarely visit. The images revealed vast areas of bare rock that, just a few decades before, had been crowded with some 500,000 pairs of nesting king penguins and their chicks. It appeared that the colony—the world’s largest king penguin aggregation and the second biggest colony of any of the 18 penguin species—had shrunk by 90%. Nearly 900,000 of the regal, meter-high, black, white, and orange birds had disappeared without a trace. “It was really incredible, completely unexpected,” recalls Weimerskirch, who works at the French national research agency CNRS...
...King penguins should be relatively easy to study. Unlike their ice-bound cousins, such as emperor penguins, king penguins live on islands dotting the subantarctic region. That means they can be reliably and repeatedly counted in satellite images over time, and scientists can camp alongside their breeding colonies to observe them. (Other ice-dependent species, like emperor penguins, are more peripatetic.) During the lengthy breeding season, the parents trade off tasks, with one incubating eggs or rearing fluffy brown chicks while the other heads to sea to catch fish and other sea creatures. These foraging round-trips can cover 500 kilometers or more, electronic tags attached to the birds have shown.



...REAMS OF DATA remain to be digested. But the researchers have already ruled out some possible explanations for the massive penguin decline. Land predators, for instance, don’t seem to have played a role. Examinations of chicks and adult penguins, as well as excavated bones, revealed no signs of cat or mouse bites, and the team’s cameras recorded no attacks. (Rabbits, seen on previous expeditions, were curiously missing.)Nor, it seems, had the penguins simply moved somewhere nearby. A second smaller colony on the island, a natural site for relocation, had just an estimated 17,000 pairs, not enough to explain the massive drop-off in the main group. And Bost says there’s no obvious indication—in satellite images, for instance—that the colony relocated to some other island.

That leaves one main explanation, Bost says: “If the penguins are not here, they died.” But what killed them?

Not disease, apparently. The team is waiting on final blood analyses, but they saw few ailing birds or fresh corpses. “We thought we’d see carrion, individuals in bad condition,” Chaigne says. But the birds looked healthy...

...Evidence that a warming ocean could threaten the penguins comes from a 2015 study that Bost and his colleagues did at a smaller king penguin colony, on Possession Island, some 160 kilometers west of Île aux Cochons... The study, published in Nature Communications, analyzed 124 foraging routes taken by 120 tagged birds over 16 years. It found that in years when the polar front moved south, the penguins had to travel hundreds of kilometers farther. During “these very unfavorable environmental conditions,” the researchers wrote, “the penguin breeding population experienced a 34% decline.”

Building on that study, a 2018 paper published in Nature Climate Change forecast that warming seas and other environmental changes could cut king penguin numbers by half by the end of the century.

Whether that scenario explains the Île aux Cochons crash may never be entirely clear...

[sinkingfeeling]

1. Breaks my heart.

[lastlib]

2. Wow! Unbelievably sad! I wonder...

...if there is any correlation to this:

150,000 Penguins Died of Starvation

This report came out at nearly the same time that Antonin Scalia died. I remember posting the two events on DU and adding the snarky comment that I was sure going to miss those penguins. I DO miss those penguins, and I sure as hell hope Scalia stays dead.

[Cetacea]

3. We are in the Sixth Great Extinction

And humans seem to have a sense of hubris that somehow it doesn't concern us.
On a related note, starlings, mostly regarded as pests by most people and extremely common, have completely vanished in my area. It happened very quickly.