A species of shy and elusive waterfowl continues to be a source of controversy between Parks Canada and a tourism advocacy group.

For more than a decade now, the mid-Maligne River has been closed to commercial rafting and other recreational boating as a precautionary measure to protect harlequin ducks – birds which are usually more associated with the ocean than with alpine waterways.

“These are sea ducks,” biologist Beth MacCallum explained during a recent lecture on the creatures at the Foothills Research Institute in Hinton. “You don’t normally think of sea ducks in the Rockies, but that’s what they are.”

Harlequins do spend a significant amount of time away from the ocean, however, and will venture from the Pacific as far east as the foothills between Jasper and Hinton during the summertime to breed and raise their young before returning to the coast for the winter.

It’s due to these habits that Parks Canada decided to ban commercial rafting along an 18-kilometre stretch of the Maligne River in 1999. The federal agency says the move was necessary to protect the sensitive species’ habitat, but the Association for Mountain Parks Protection and Enjoyment (AMPPE) has long argued the rules are overly restrictive and it continues to call on Parks to re-open the route to rafts and other recreational watercraft.

“There are kayakers that would love to use that portion of the river,” said AMPPE executive director Monica Andreeff. “And this is a world-class whitewater rafting opportunity.”

Andreeff noted that Parks hasn’t even been keeping track of how many harlequin ducks frequent the mid-Maligne River since the closure. According to volunteer counts she’s seen, she said there are hardly any of the birds in the area at all.

“Since rafting was eliminated from the river the ducks have declined to the point where there’s maybe one, maybe two ducks that have been glimpsed,” she said.

But Shawn Cardiff, an integrated land use planning manager with Jasper National Park, said the number of ducks isn’t the issue; it’s the protection of habitat that’s important.

“The closure isn’t predicated on the numbers changing,” he said. “It’s a precautionary closure to make sure the habitat is secure.”

Besides, he added, harlequin ducks are notoriously difficult to count as they nest in hidden areas and are extremely shy around human beings. That’s a challenge MacCallum said researchers in other areas constantly run into when attempting to count the birds.

“Unless you’re actually looking for them, most people’s eyes will just pass right over them,” she said. “And they’ll see you before you’ll see them.”

The peculiar birds form pair bonds on the coast and then the females bring their mates back to specific breeding streams in the mountains. Individual females have been observed returning to the same nesting area up to six years in a row.

By the end of June, the males return to the coast while the females remain to raise the little harlequin ducklings, which is no easy task. The birds face larger numbers of predators in this region than they do near the ocean and so the moms and their broods must develop a series of defensive strategies in order to survive.

“They do lose weight over the summer, the moms, because it’s a big job for them,” MacCallum explained.

One of the ducks’ main strategies to avoid predators is to be extremely wary of potential threats, which is a big part of the reason for their elusive nature around human beings. MacCallum said there is no question that the persistent presence of people in places like the mid-Maligne would have an impact on the harlequin population.

“They are sensitive to disturbances on the shore or in the water,” she said. “Too much activity on the shore or in the water and they’ll be pushed away.”

Almost half of the ducks’ range is in national or provincial parks or otherwise protected areas, MacCallum noted.

Andreeff, however, pointed to a recent study which suggested another reason for the ducks’ decline in areas like the Maligne – artificial fish stocking.

“We hypothesize that the ongoing and widespread introduction of fish into historically fishless waters throughout North America may have contributed to the current low productivity and recruitment measured in populations of harlequins by reducing quality of breeding habitat,” reads the abstract of that article, published in the Canadian Journal of Zoology in 2009.

Andreeff noted that trout and char were introduced into Maligne Lake in the 1920s and the fish have since moved into the mid-Maligne where they eat the same insects that the harlequins depend on as a food source.

“The ducks have to compete for their food source and so they’ve gone to where there’s no competition,” Andreeff said.

Cardiff said he is aware of that research and while it’s an “interesting hypothesis,” the fact that the fish have been present for 80 years in the river doesn’t explain population changes that began to be observed about 18 years ago both on the Maligne and elsewhere.

“What we don’t know is why, precisely, the harlequin duck populations have appeared to decline on that reach and why they have appeared to decline quite broadly in Alberta since 1994,” he said.

Andreeff maintained that Parks should back up its closure policy with more recent population figures.

“They don’t want to spend the money. They don’t have the resources to monitor the ducks,” she said. “There’s a real reluctance to really examine this issue in a serious way.”

Parks Canada stands by its policy, however, and Cardiff said the agency will consider any new scientific evidence that is brought forward which challenges its basis for the river closure.

“If people want to advance a proposal, we’ll give it serious consideration,” he said.