AILSA CHANG, HOST:
Maine's population of rare Atlantic puffins took a hit this year. The number of chicks that survived this past summer plummeted compared to previous summers. The state's coastal waters are among the fastest warming on the planet, so the bird's fate is a test case for how climate change could disrupt marine ecosystems worldwide. Maine Public Radio's Fred Bever reports.
FRED BEVER, BYLINE: The little clown-colored birds are abundant in Canada. But in the U.S., they were hunted to near extirpation by the early 1800s. Scientists later helped them reestablish several island colonies off Maine, where they now number around 3,000. Over the last decade, though, a series of marine heat waves and intense storms upended their living conditions. This year was one of the worst yet, and the number of puffin chicks to live through the season plunged.
LINDA WELCH: In some cases, it was actually significantly worse than we've seen in the past.
BEVER: Linda Welch is a biologist with the U.S. Fish and Wildlife Service. On one island, Welch says 90% of the nesting puffins failed to raise a chick.
WELCH: Many of the chicks that we classified as fledging, reaching the age where they leave their burrow and go to sea, the birds were kind of 40- to 50% smaller than we normally see. We were calling them micro-puffins.
BEVER: The birds faced a complex of challenges. Nests were flooded by some of the heaviest rains in 100 years, exposing chicks to cold and predators. Their parents had a hard time finding herring and other North Atlantic prey they usually dive for, which scientists think may have retreated to cooler waters too deep or far off for the birds. The puffins did bring in a lot of butterfish, a more southerly species that's been showing up in force in heat wave years. The thing is, butterfish are too big for young puffins to swallow.
WELCH: There was a puffin chick that had reached the age where it should have been able to leave its burrow. It was fully feathered. It was dead in the burrow, and there were, you know, probably 10 or 12 carcasses of butterfish surrounding it.
BEVER: Other ecosystem dislocations are emerging in the Gulf of Maine. New research suggests, for instance, that a big incursion of voracious squid during an extended heat wave was decisive in the collapse of a prized shrimp fishery. Formerly itinerant black sea bass are starting to stick around all year and spawning. Their juveniles might even become a new food source for other species, such as puffin chicks.
DON LYONS: Working with puffins in Maine, we're seeing the harbingers of climate change every day.
BEVER: National Audubon Society seabird expert Don Lyons says puffins provide a unique window on global warming on how even small shifts in the range or timing of any one species occurrence can influence the fate of many others.
LYONS: I tend to think of puffins as a bunch of researchers. They're going out and sampling our marine ecosystem all summer, many times a day. They're really telling us to be concerned, you know, to pay attention.
BEVER: Puffins can live up to 30 years, providing some resilience against a bad year. Lyons says their future in Maine may depend, though, on just how often those bad years keep rolling in.
For NPR News, I'm Fred Bever in Falmouth, Maine. Transcript provided by NPR, Copyright NPR.