Atlantic Puffin chicks in Maine, like this month-old puffling, were plump and plentiful this year at the three colonies Audubon oversees. Photo: Steve Kress/Audubon

Though they sit on three remote, stark, and treeless islands, the Atlantic Puffin colonies Audubon manages off the Maine coast were positively brimming with life this summer. Seabird stewards there recorded a banner breeding year marked by large numbers of birds and particularly plump pufflings, as the chicks are (adorably) known.

The number of breeding puffin pairs at Eastern Egg Rock grew from 150 in 2016 to 172 this summer, marking the biggest year-to-year increase since 1981, when the birds first recolonized the island after a century of absence. At Seal Island National Wildlife Refuge, 86 percent of the breeding pairs successfully fledged a chick, and Matinicus Rock saw a strong 80 percent success rate. For contrast, just 10 percent of Seal Island puffin pairs fledged a chick in 2013.

“It all came together wonderfully this year,” says Steve Kress, director of Audubon’s Seabird Restoration Program. In recent years, puffin parents have sometimes struggled to catch enough food for their chicks. But this summer brought a reprieve from warming ocean waters and a rebound of fish stocks. For the dedicated team at Project Puffin, the restoration effort Kress launched in 1973, the positive outcome was a reminder of the importance of their work.

“These good years don’t come around as often as perhaps they once did because of the warming water,” Kress says. "So when a good year does come around, it’s important that these conservation islands be there.”

He attributes the colonies' success this summer to a healthier-than-usual food web. Springtime surface water in the Gulf of Maine was a half-degree Celsius cooler than last year, and that colder water supported a robust plankton bloom. Soon, small fish arrived to feast on the plankton, and then in the summer the puffins fed those fish to their young.

Project Puffin found that the young birds had a healthy diet of cold-water fish like hake and herring. Matinicus Rock fledglings weighed in at 350 grams, on average, compared to 250 grams in 2012, when the sea surface was warmer. Building up a healthy store of fat is critical to sustain the young birds as they spend all winter on the open ocean.

In years with warmer water and weaker plankton blooms, the fish go elsewhere to forage, and pufflings go hungry.

Warming waters have made it harder for puffins to find nutritious fish like Atlantic herring in recent years.

Warming waters have made it harder for puffins to find nutritious fish like Atlantic herring in recent years, Kress says. Instead, since 2011, Acadian redfish have become an important food for Maine puffins. Once overfished, the species has bounced back in response to better management. Haddock also have rebounded and become an important food source for puffins. “Having these other fish added as opportunities for the fish to eat gives them a better chance at adapting to warming waters,” Kress says.

However, Trump administration policies could hurt that important food supply. Interior Secretary Ryan Zinke has proposed allowing commercial fishing in Northeast Coral Canyons and Seamounts Marine National Monument, a roughly 4,000-square-mile sanctuary 130 miles southeast of Cape Cod that was protected in 2016. “A place like the national monument is important for two reasons: That’s where puffins go in the winter from Maine, and that’s a place where some of these deepwater fish like Acadian redfish and white hake are breeding," Kress says. "You can’t just protect the nesting islands" if you want to protect puffins.

The potential for commercial fishing in the monument is concerning, but it's important to not let this year’s positive puffin news get overshadowed. Kress and his team may not be able to control long-term trends in ocean temperatures or fish stocks or government policy, but they’re dedicated to doing what they can to protect the birds—and it’s paying off.