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Snow geese devouring habitat Wildlife expert warns population spike of migratory birds is cause for concern

By Matthew Hoekstra
Staff Reporter
Nov 02 2006

Rabbits aren’t the only creatures breeding like bunnies.

Snow geese are migrating to the Fraser estuary in growing numbers and the burgeoning population is raising the prospect of an ecological disaster. Wildlife officials want to ensure the population doesn’t spiral out of control and mirror habitat destruction in the Arctic caused by a massive mid-continent population of the migratory birds.

Sean Boyd, migratory bird ecologist with the Canadian Wildlife Service, predicts the lesser snow goose population could reach 100,000 this year—a jump from last year’s count of 80,000. Good weather and climate on northern breeding grounds, on Wrangel Island in Russia, has much to do with the high return. Boyd said the snow geese are arriving earlier and nesting earlier.

“It’s probably this whole global warming thing that’s happening,” he said. “Everything is happening earlier because of this warming trend, and more birds are nesting, and they’re probably in better condition.”

Historically, wildlife officials have seen a complete bust in snow geese reproduction every three years due to weather, but that hasn’t happened in the last several years, said Boyd.

The greater the population, the greater the strain on habitat. Snow geese feed on intertidal marsh plants along Richmond’s Sturgeon Banks and Delta’s Westham Island and farm fields—when they’re not frozen. “They’re knocking (the marsh) down pretty far. So there’s a concern the population may be too high, or quite a bit too high and may have to be reduced,” said Boyd, who has measured the depleting marsh for years.

“If it’s knocked down too far, to the point where they don’t have enough food to sustain a population, there could be a real problem down the road,” he said.

The birds begin to arrive in the Fraser River estuary in October and move south to the Skagit estuary in December. They return to the Fraser in the spring before making the 4,000-kilometre journey back to Wrangel Island in April.

In Eastern Canada, populations of migratory waterfowl were curbed too late. Snow geese there ate out their habitat on breeding grounds, destroying a third of it and bringing another third to the brink of vanishing.

“They’re having an effect on other systems at other times of the years, and those are having a cascade effect on other species that would be dependent on those marshes as well,” said Boyd.

Boyd said there has been “some interest” in raising the snow goose hunting limit. Hunting is permitted on farm land. The last change to the hunting season came three years ago, when officials extended the fall hunt by a month.

Said Boyd, “Who knows, we may have to do something a little bit more drastic than that.”

Brad Arner, manager of conservation programs for Ducks Unlimited, said the rising population brings the challenge of maintaining enough food for all migratory birds. One solution is to encourage farmers to plant winter cover crops.

“It’s definitely nice to see the birds and the big numbers, but there’s a point where too many can be a concern.”