Every winter, a large number of bald eagles migrate to the lower Fraser Valley, creating the world’s largest eagle congregation, according to biologists. The eagles are currently gathering along the Harrison River to feast on returning salmon, attracting birds from as far as Alaska and Yukon. This seasonal phenomenon occurs from November to February when northern lakes and rivers freeze, forcing the eagles to seek food in the lower region.
David Hancock, a renowned bald eagle researcher and the founder of Hancock Wildlife Foundation, explains that these eagles are mostly northern breeders escaping the harsh winter conditions in their home territories. As the lakes and rivers in the northern regions freeze, the eagles head south in search of food.
An estimated 35,000 to 50,000 eagles pass through the area each winter, with the current peak of the salmon run providing ideal conditions for the birds. Ornithologist Rob Butler, honorary director of the Pacific Wildlife Foundation, notes that a successful salmon run keeps the eagles in the area for an extended period. In lean salmon months, the eagles move to the coast to hunt ducks along the Salish Sea shorelines.
The Harrison River, known for its abundant salmon population, is a preferred location for the eagles’ congregation due to its productivity. This gathering also signifies the remarkable recovery of bald eagle populations since the mid-20th century when their numbers dwindled significantly.
The decline in eagle populations was linked to the widespread use of the pesticide DDT, which led to thinning eggshells and population devastation. However, conservation efforts and a halt to hunting and poisoning have contributed to the eagles’ resurgence.
Apart from their ecological role in maintaining ecosystem balance by scavenging on salmon carcasses, the eagles also boost tourism in the area. The annual Harrison Eagle Festival has become a popular attraction for birdwatchers and photographers, drawing crowds eager to witness the majestic birds in action.
Visitors, like Dan Woodstra, express awe at the sight of the eagles in their natural habitat, describing the experience as magical and unforgettable. The eagles are expected to remain in the region until February before embarking on their journey back north.