From the 
Washington Post:
 At the Maine Coastal Islands National Wildlife Refuge,  the tiny bodies of Arctic tern chicks have piled up. Over the past few  years, biologists have counted thousands that starved to death because  the herring their parents feed them have vanished...
What’s happening to migratory seabirds? Biologists are worried about a  twofold problem: Commercial fishing is reducing their food source, and  climate change is causing fish to seek colder waters, according to a  bulletin released Tuesday by the U.S. Fish and Wildlife Service. “We’ve  seen a 40 percent decline of Arctic terns in the last 10 years,” said  Linda Welch, a  Fish and Wildlife Service biologist at the refuge...
Biologists at the Maine refuge are not sure whether herring sought  colder waters elsewhere or went deeper, but they are no longer on the  surface, from which Arctic terns pluck them. While other birds can dive  deep for food, Arctic terns cannot.
“They’re not getting herring,  so they bring butterfish that the chicks can’t swallow,” Welch said. “So  they starve to death. You have thousands and thousands of chicks dying.  It’s very sad.”
Arctic terns are famous, of course, for having the world's longest migration - from Antarctica to the Arctic - and back.
Arctic terns arrive at the Maine islands after a month of flying from  the Antarctic, about 470 miles a day — 14,000 total — low on energy,  longing for a bite. If they lack food and energy, “they can’t keep the  gulls off them,” Welch said. Gulls eat terns.