DAVID GREENE, HOST:
There is a string of islands off the North Atlantic coast called the Isles of Shoals. They straddle New Hampshire and Maine. They were used as seasonal fishing camps in the 17th century. But now they are running thin on fish. Researchers have set up on White Island off the New Hampshire coast to study birds who are not getting enough herring and other bait fish. Here's Stephanie Leyden from member station WGBH.
STEPHANIE LEYDON, BYLINE: It's only a half hour boat ride up to New Hampshire's Isles of Shoals.
(SOUNDBITE OF MOTOR BOAT RUNNING)
LEYDON: But the islands - there are nine in all - feel remote. One of them is little more than a hill of rocks with a majestic, old lighthouse perched on top.
ELIZABETH CRAIG: We're right next to the lighthouse. And you'll probably hear the foghorn as we are walking around, as well.
(SOUNDBITE OF FOGHORN)
LEYDON: Liz (ph) Craig has taken up residence in the lighthouse keeper's cottage. She's a University of New Hampshire biologist, here for the birds.
(SOUNDBITE OF TERNS SQUAWKING)
LEYDON: They're terns, a threatened species. Thousands of them spend the summer on the island next door.
CRAIG: Watch out 'cause it's quite slippery.
LEYDON: On a breezy afternoon, she leads me across a rocky stretch that connects to the neighboring island.
CRAIG: OK. Let's stop here.
LEYDON: Smaller than seagulls, the terns are white and gray with black heads and bright orange beaks. And with so many circling so close, it's hard not to think of Alfred Hitchcock's famous movie.
(SOUNDBITE OF TERNS SQUAWKING)
LEYDON: Craig always wears a big straw hat.
CRAIG: They all dive bomb and hit you as hard as they can in the head, as well as throwing their poops at you. I mean, they do everything that they can to try to scare you off 'cause they perceive you - us - as their predator.
LEYDON: Their message - don't mess with mama bird or papa. They've come here to breed. Tiny nests are everywhere in rock crevices and in the tall grass where Craig has retrieved a squirming chick.
CRAIG: So (laughter) this bird is almost ready to fly.
LEYDON: The chick's nipping at her fingers as she holds its wing against a ruler.
CRAIG: We've been doing these same wing and weight measurements ever since these chicks hatched. And it's our way of keeping track of their growth.
LEYDON: It's like a well-baby visit with a pediatrician.
CRAIG: That's right. That's right. They get their checkup.
LEYDON: The checkups show many of the chicks are underweight, indicating they're not getting enough of the food Terns favor, herring and other bait fish. Lobstermen rely on those same fish, according to Jennifer Seavey, who directs the New Hampshire Tern Research Program. She says the birds yield information used to manage and sustain local fisheries.
JENNIFER SEAVEY: You can see how the terns would be a great sort of indicator of what's going to happen next for the lobster industry.
LEYDON: It's one reason scientists want colonies like this to thrive. Also, it's been tough for the tern. They were once hunted and put on ladies' hats. More recently, development has encroached on their nesting areas. And there's an age-old predator...
(SOUNDBITE OF SEAGULL SQUAWKING)
LEYDON: ...Seagulls. They poach eggs and even adult terns. When humans are around, the gulls mostly stay away. Just by being here, Liz Craig and her team protect the terns.
CRAIG: The chicks are just starting to fly. And for me, it's the most amazing moment because you've seen all the hard work that you've put in and that they've put in actually come to fruition.
LEYDON: In a few weeks, the terns will take off for destinations as far as Argentina. Research gathered on this island will be shared with scientists studying terns and ocean health around the world. For NPR News, I'm Stephanie Leydon on the Isles of Shoals, N.H. Transcript provided by NPR, Copyright NPR.