Seabird die-offs in Alaska are natural events, but the massive rate of starved dead birds washing ashore this month is as puzzling as it is unprecedented.
Two weeks ago an estimated 8,000 murres were found laying dead by David Irons, a retired seabird biologist from the U.S. Fish and Wildlife Service. “I never thought I would see that many dead birds on one beach,” Irons told ThinkProgress.
But it was this week when the story got national attention, as some Alaska researchers have publicly said the number of dead birds found in a beach 60 miles southeast of Anchorage is beyond anything experienced in the last few decades.
“It’s fair to say that that’s never been recorded before,” said Rob Kaler, a U.S. Fish and Wildlife Service seabird biologist, in an interview with ThinkProgress.
Researchers said an uptick in dead bird sightings started in late March, a rare time to observe bird mortality. Why sightings began so close to spring, how many birds have died since, and most importantly, why it manifested with such force on the murre population is a mystery. Climatic factors may be disrupting food supplies, researchers said, but they still are not sure.
“There are other species of seabirds that are being found on beaches, but nothing like the numbers of murres,” said Kaler.
Common murres are about 18 inches long and vaguely resemble penguins. They have small wings in proportion to their body that propel them during deep underwater fishing dives. These seabirds are one of the most abundant in Alaska, and prefer sea over land, since their legs work better on water during lift-off. Murres are also considered an indicator species — they help scientists know the conditions of other seabird populations, as well as fisheries.
Since the dead birds were found, the Fish and Wildlife Service has covered many miles of Alaska’s coast to learn if this die-off was an isolated event. They’ve found that it wasn’t — other birds, like Kaler said, have also been dying off, though in smaller numbers. What’s more, murres are behaving strangely in multiple ways. Kaler said murres have been abandoning their nests in locations where that has never happened before. Stranded murres are also being found inland and near turbid, shallow water bodies where it’s impossible for them to fish. These bizarre flight patterns “were likely” wind assisted, Kaler said. “But why were they even that far inland in the first place?”
CREDIT: (AP Photo/Mark Thiessen)
Researchers have few real leads on what’s happening. So far the only thing they’re certain of is that seabird mortality has to do with its food intake.
“We know [murres] are starving but what we don’t know is the mechanism for why they are starving,” said Kaler, adding that perhaps something’s wrong with food distribution or its abundance. Bacteria or viruses don’t seem to be the issue here, since some 100 carcasses were sent for testing at the National Wildlife Health Center in Wisconsin, and no traces of toxins or diseases have been found.
With poisoning and illness out of the picture, scientists are turning their attention to climate. That’s because these die-offs, also known as “murre wrecks,” are natural events that happen particularly during storms that prevent seabirds from fishing. El Niño warming trends are also associated with murre wrecks, as the weather pattern affects prey patterns. If that’s the case, this could be a bad year for murres, as El Niño is forecast to be one of the most powerful ever recorded.
An El Niño of such magnitude, moreover, adds to the recent warming trend in Alaska. “In 2014 we had above average sea surface temperature in the north Pacific and Gulf of Alaska, and it never really cooled down through the winter,” said Kaler. “And then 2015 proved to bring record-breaking temperatures as well.”
Last year was the second hottest on record in the United States since data collection began in 1895, according to the National Oceanic and Atmospheric Administration. NOAA said 2015 was also the 19th consecutive time that average temperatures in the U.S. exceeded the 20th century average.
Scientists can’t say how this warming trend has affected fish in Alaska. There is no reliable data on fisheries, but Irons, the seabird biologist who discovered the beach die-off, told local media that it’s widely known that fish live in narrow bands of temperature. “Are [fish] going deep? We don’t have any evidence of that, but the birds eat them and we know [fish] are not around when it’s warm,” he said to Alaska Public Media.
Indeed, research has found that warming waters influence fish behavior. These findings have come at a time when virtually the entire scientific community believes the planet is warming because of emissions, deforestation, and other human activity. Plus, a warming planet means more extreme weather events, studies show, a trend that’s been observed globally.
For his part, Kaler seems to lean towards climate change as the underlying culprit of Alaska’s murre die-off. He also expressed concerns of what will happen to the ecosystem if climate extremes observed continue in the long run. “If these storm systems and El Niño events and warm bodies of water continue for the next 10 years, it’s going to have effects on the entire ocean system,” he said.
Unprecedented seabird die-offs, meanwhile, have been recorded from California to Canada for some time now, according to published reports. Starvation has been reportedly the main cause of death.