Researchers to track northern gannets after Nfld. chicks left to starve

A gannet flies over its nesting grounds Wednesday, July 25, 2012 on the Bonaventure Island in Perce, Que. (Jacques Boissinot/ THE CANADIAN PRESS)

ST. JOHN'S, N.L. -- Researchers at Cape St. Mary's Ecological Reserve in southeastern Newfoundland are trying to solve a sad mystery: why northern gannets have once again abandoned their chicks to starve.

Bill Montevecchi, a biologist at Memorial University of Newfoundland, said Thursday it's the third season since 2012 that the usually attentive parents have left their young.

"There's a lot of chicks that have died," he said in an interview. "The breeding success, my guess would be 30 or 40 per cent compared to a good year of 80 or 90 per cent."

Montevecchi is working with another scientist from the U.S. Fish and Wildlife Service to come up with answers by tracking the adult birds over the next year. They're attaching newly developed silicon harnesses with solar-powered devices that can be picked up on cell phone towers along the coasts of Newfoundland, Nova Scotia and the northeastern U.S.

"Where do they go? That's the big question," said Montevecchi.

Gannets tend to mate for life and live 20 years or more. Major reproductive failures would have to continue for at least another seven years to diminish overall population numbers, he explained.

Still, researchers are baffled about what is happening. Monogamous gannet pairs meet at the same nest year after year, taking turns doting on first the egg and then the chick from spring until late September when they head south for the winter, Montevecchi said.

One parent typically stays in the nest to fend off predators such as eagles, gulls and other gannets while the other gathers food at sea.

A suspected culprit in past years was warmer water and its effect on fish hunted by the birds. The abandonments have seemed to previously coincide with a sudden jump in water temperature in early August as gannets were seen far outside their usual foraging zones.

The pattern suggested fish on which the gannets rely were being driven into deeper water out of easy reach.

"We know they're hungry," Montevecchi said. "These birds are now, in a way they haven't in the past, feeding at the fishing boats."

Researchers recently captured a photo of a gannet with what appeared to be a sculpin in its mouth -- a bottom feeder not part of the bird's usual diet that was likely caught accidentally and thrown back by fishermen.

Research assistant Abigail Hann, a biology student at Memorial University, has spent the summer at Cape St. Mary's.

"It's pretty sad," she said of the chick losses. "I think it's most important to let people know this is happening, and to figure out why it's happening.

"Maybe we can do something about it ... especially if it's related to climate change. That's something we're all having a part in causing."

Cape St. Mary's, a two-hour drive southwest of St. John's, is the most southerly of the world's 40 known gannet colonies. It is also one of the most accessible, where visitors on foot can get within metres of Bird Rock for an unusually close look at hundreds of nests.