The number of eagles flocking to Brackendale appears to have dropped this winter because of low salmon returns on the Cheakamus River, local bird watchers say.

Thor Froslev, who organizes Brackendale's annual eagle count, says the average count is 1,750 eagles.
(CBC)

From late November to February, Brackendale usually teems with eagles that feed on the carcasses of salmon that have finished spawning in the Cheakamus River near Squamish.

For years, bird lovers have also descended on the small town north of Vancouver to witness one of the highest concentrations of bald eagles anywhere.

The sight of the majestic birds is so popular, the local art gallery runs a Bald Eagle Festival that draws hundreds of people every January.

Nearly 4,000 of the birds were spotted during Brackendale's annual one-day eagle count in 1994, earning it the title of "World Eagle Capital." On average, 1,750 eagles are counted each year.

After spawning, the mature salmon die and eventually wash ashore, bloated, soft and rotten — a perfect meal for bald eagles, said Thor Froslev, who organizes Brackendale's annual eagle count.

"They like their food five to six weeks dead so it's easier to get meat off the bone," said Froslev.

But this season, the salmon run was smaller than usual, and that means less food and fewer eagles, said Froslev.

The actual number of eagles this year will be clearer when the count gets underway Sunday.

So far, there is no hard data on how much smaller the salmon run is this year either, but experts at the Department of Fisheries and Oceans confirmed the run is below average.

"We don't have an answer [why] — whether it was too warm out there, whether the salmon farm and their lice were a part of it," Froslev said on Wednesday.

No one reason for changing numbers: biologist

Edith Tobe, a biologist and director of the Squamish River Watershed Society, said there is no single reason for fluctuating numbers of salmon.

"Between global warming, commercial fisheries, natural or artificial diseases — these all have an impact on the salmon and their survival rates," said Tobe.

Meanwhile, Froslev said experts at Fisheries and Oceans Canada told him that every four to five years, the salmon run is smaller than normal, and it's no cause for concern until it starts happening year after year.

Last August, the B.C. government laid five charges against CN Rail in connection with a 2005 train derailment that spilled 40,000 litres of sodium hydroxide into the Cheakamus River, killing an estimated 500,000 fish in an 18-kilometre section of the river.

But Fisheries officials told CBC the spill was not a factor in the low salmon returns because it would not have affected the run of chum salmon returning this year, which would have hatched before the derailment.