Thousands of bald eagles descend on BC’s Fraser Valley for winter migration
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Every winter, thousands of bald eagles descend on the lower Fraser Valley – a migration biologist says is the largest gathering of eagles in the world.
The spectacle is well underway along the Harrison River, where eagles are flocking to returning salmon from as far away as Alaska and the Yukon.
From November to February, the shores around Harrison Mills become seasonal feeding grounds for the birds as northern lakes and rivers freeze over, says longtime bald eagle researcher David Hancock.
“Most of these are northern breeders who come here to escape the northern winter,” said Hancock, founder of the Hancock Wildlife Foundation, which specializes in raptor conservation efforts.
“When lakes and rivers in the Yukon, Alaska and northern BC freeze over, their fish go under the ice. So they come south.”
Thousands of eagles have flocked to the Fraser Valley. The birds gather in the Harrison Mills area to feed on salmon as part of the annual migration. Our bunnet britches had gone to see the seasonal spectacle.
He estimates that 35,000 to 50,000 birds visit the area each winter.
Salmon production is now at its peak, with experts saying conditions are ideal.
“We’re right in the middle of the big salmon run and, of course, the eagles are back,” said ornithologist Rob Butler, director emeritus of the Pacific Wildlife Foundation. “If it’s a good run of salmon, the eagles will stay on those rivers a long time.”
Butler says that during months when there are not enough salmon in the river, the birds move to the coast along the Salish Sea and hunt for ducks the rest of the winter.
He added, “So of course, the ducks are hoping there’s going to be a big salmon run for them.”
The Harrison River is one of Canada’s most productive salmon waterways, which is a major reason the migration is concentrated here rather than elsewhere in the province, Butler said.
‘A remarkable comeback’
Both experts say the annual congregation is also evidence of how far bald eagles have bounced back after population declines in the mid-20th century.
When Hancock first surveyed in the 1950s and 60s, he counted only three breeding pairs in the Fraser Valley. Today, he says there are about 700 pairs, which is a “remarkable comeback.”
According to Butler, this collapse was linked to the widespread use of the pesticide DDT, which thinned eggshells and devastated populations throughout North America.
“Then the numbers started coming back because people stopped hunting them and stopped poisoning them.”
Eagles keep the ecosystem and tourism thriving
Eagles also help maintain balance in the Harrison River ecosystem by scavenging salmon carcasses and naturally limiting fish and duck populations.
“They are the conductors of the gorgeous choreography that we see here,” Butler said.
He says their presence also draws crowds and the Harrison Eagle Festival has become a major hub for bird lovers and photographers.
“It was incredible,” said visitor Dan Woodstra, who boarded a jet boat as part of an eagle watching tour along the Harrison River.
“I don’t think I’ve seen eagles like this anywhere else. It’s truly magical to see such a creature in its element doing its thing.”
Experts say the eagles will remain here until February before returning north.
