Mass Die-Off of Puffins
Hundreds of “severely emaciated” puffin carcasses have washed ashore on an Alaskan island, and researchers believe thousands more have died at sea as warming waters continue to shrink their food supply.
Between October 2016 and January 2017, inhabitants of St Paul Island in the Bering sea found the starved bodies of more than 350 seabirds, primarily tufted puffins.
Analysing the location of bird carcasses and wind data, Timothy Jones at the University of Washington in Seattle and his colleagues estimated that between 3000 and 9000 birds died in total.
When they examined some of the bodies, they found no signs of infection or unsafe levels of toxins. “Collected specimens were severely emaciated, suggesting starvation as the ultimate cause of mortality,” Jones wrote.
Tufted puffins, which accounted for 79 per cent of the bird carcasses found, eat fish and marine invertebrates, which in turn eat phytoplankton. But changes to atmospheric conditions, including the ongoing heatwave, have massively disrupted the marine ecosystems, he wrote. There is less winter sea-ice, and warmer temperatures have been linked to fewer forage fish, crustaceans and other prey animals as they either die off or move north to cooler waters.
Almost all the puffins they found were adults in the process of moulting, which makes them flightless for up to 40 days and requires more nutritional energy than normal.