Dovekie respond to Climate Change
by Nate Swick
For all their relative scarcity in much of the ABA Area, Dovekie (called Little Auk in Europe) are among the most abundant seabirds in the world with a breeding population estimated from 40-80 million individuals. That population, which disperses across much of the North Atlantic in the winter, is sustained largely by the abundance of large, fat-rich, copepods of the Calanus genus, of which the birds can individually devour up to 65,000 per day.
For a bird that breeds across the famously chilly coast of Greenland and east to northern Norway, a rising climate will likely have a significant affect on the species's well-being. And researchers studying Dovekie have discovered that the birds are already changing their habits to take advantage of a new normal.
For three years, in summer, the researchers studied three colonies of little auks on either side of the Greenland Sea. The difference in surface water temperatures between the warmest and coldest site is 5°C. The warmest site, located in Spitsbergen, reproduces the conditions predicted for the late 21st century in the coldest site (East Greenland). Such temperature differences lead to major changes in the abundance and average size of zooplankton, reducing the quality of little auks' food resources (copepods).
Surprisingly, the birds have managed to make up for the warming of surface waters in the Greenland Sea by altering their diet and extending the duration of their foraging trips at sea. They travel further and for longer in order to feed in areas where foraging is more successful.
Thought the Dovekie have been able to adapt on the short term, traveling longer distances for lower quality food is hardly a recipie for success on the long term. It's perhaps worth noting that the last three years have seen Dovekie wintering farther south in record numbers, particularly in the coastal southeast United States where they are infrequent at best. It's a reminder that what is often considered a windfall for the birders is often not nearly as bountiful for the birds themselves.
Further research, investigating the affect of sea temperature change on the species's winter survival, is ongoing.