These downy ducklings aren't just cute — they're a Gros Morne success story

The downy, common eider ducklings ecologists are tallying more and more of in Gros Morne National Park aren't just adorable — Parks Canada says it's indicative of the success it has had in helping foster a thriving population of the birds.

Although two coastal islands in the park are prime eider duck habitat, prior to 1993, the park had no record of the ducks within its boundaries. That year, researchers discovered three nests on Stearin Island, off the coast of Cow Head.

Although the ducks aren't considered endangered, at that time their numbers in Newfoundland and Labrador were low, and scientists rejoiced at the opportunity to encourage a population to establish itself in the park.

But there was a problem: the eiders weren't alone on Stearin island.

"We have a huge colony of gulls," said ecologist Shawn Gerrow.

"Of course, those gulls like to eat eider eggs."

Parks Canada

Gull vs. duck

Eider ducks are the largest ducks in the Northern Hemisphere, and can tip the scales between three to four kilograms — that's verging on the size of a small Canada goose. 

While those sizeable adult eiders aren't bothered by gulls, the females do need to leave their nests about once a day to feed and drink, leaving their eggs vulnerable to the hungry herring and black-backed gulls abundant on Stearin Island.

"At the time parks staff said, 'Can we figure out a way to protect them?'" Gerrow.

Staff settled on trying out a type of nesting box, adapted to suit the eiders' needs.

"They're actually more like a nest cover. You take a piece of plywood — that's put down, and it's just high enough off the ground that the eider ducks can crawl under," Gerrow told CBC Radio's Corner Brook Morning Show.

"They're able to crawl underneath that nest box, they build their nest, and their eggs are protected from the gulls."

Parks staff put 20 such nest boxes out, each of which could cover up to four eider nests from egg-loving gulls.

S.Gerrow/Parks Canada

Egg-citing success

Ecologists last took stock of the Gros Morne eider ducks in 2016, and were thrilled with the results: more than 400 nests, on Stearin Island as well as neighbouring Belldowns Island.

"There's more ducks there now than there are nest boxes," said Gerrow, adding that although there are now ducks nesting out in the open within reach of gulls, it's no longer a problem.

"[The duck population] is so large the little bit of predation that occurs isn't enough to impact the population."

An eider hen can lay between three to eight eggs, and Gerrow said the ducks also practice "nest fidelity," meaning the females prefer to lay their eggs in the same nest year over year.

The ducks also show fidelity to the island they were hatched on, making the Parks Canada efforts all the more important to establishing the population in Gros Morne.

"We've been seeing eider duck populations right across the island rebound. This is part of a bigger story," said Gerrow.

Parks Canada

Survival rates for ducklings are "not great," according to Gerrow, so the boxes have helped give the birds a small boost while still in the nest. The ducklings set out for sea at a fairly young age, and can be seen off the Gros Morne coastline swimming together in large groups, while the hens take turns duckling-sitting and foraging for themselves.

Staff limit their visits to the islands to every two to three years, and the colonies are off-limits to the public. That's to ensure the ducks, as well as the other dozen or so seabirds that call the islands home, get the privacy they need.

"We don't want people out on the islands, because if you have too much disturbance then the ducks can leave the nests and then you'll have excessive predation," he said.

With files from the Corner Brook Morning Show

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