Eagle counts in Squamish and Lower Howe Sound show numbers have rebounded since a low point in the 1970s and 1980s, but eagle populations continue to fluctuate based on available food sources and recent counts are quite low. The local trend is concerning, but elsewhere eagles are abundant and counting efforts are robust.
Authors: Karl Ricker, Geologist, Glaciologist, Mountaineer, Citizen Scientist and longtime birder, Whistler
Bob Turner, Geoscientist and citizen scientist, Bowen Island, Howe Sound
Reviewer: Marja de Jong Westman, Biologist, Capilano University, Lighthouse Park Preservation Society, Valdes Island Conservancy, Co-Chair: Canadian College and University Environmental Network
Banner Photo Credit: Thor Halvorson
Large numbers of bald eagles are drawn each year during the late autumn and winter to the Squamish Valley to feed on spawning salmon. Thousands of visitors flock to the Brackendale area to see this spectacle of nature. Each weekend from November to January, Eagle Watch volunteers provide visitors with telescopes or binoculars for eagle viewing along the Squamish River at Brackendale. In 2015, the Eagle Watch program of the Squamish Environment Society celebrated its 20th year. January 2016 was also the 30th anniversary of the Brackendale Winter Festival and Eagle count, sponsored by the Brackendale Art Gallery. Dozens of volunteers led by Thor Froslev count eagles each January. In 1994, 3,769 eagles were counted, a world record at the time.
Why is it important?
Bald eagles are versatile and opportunistic feeders, exploiting a wide range of foods. In coastal British Columbia, they prey predominantly on fish, seabirds, waterfowl, intertidal invertebrates, small mammals and even gull eggs and carrion of all sorts. On occasion, they do take small domestic animals. In spring most eagles migrate north along the coast or inland to nest. Some eagles nest along the coast, choosing large old trees close to shoreline areas where they can forage for food. Eagles move back to the coast after salmon spawning begins in late August and September and spent salmon carcasses become available. Eagles gorge on food when it is available and then can digest it over several days. They can survive days and even weeks of fasting which allows them to take full advantage of seasonally abundant food sources.
Bald Eagle numbers in the Pacific Northwest have rebounded tremendously over the past decades following restrictions on hunting, lead shot, and contaminants such as DDT and PCBs. There are, however, still concerns of their being exposed to persistent dioxins and furans (pulp mill pollutants). Historically the lower Squamish River Valley has been a major winter feeding ground for bald eagles along the south coast, arriving during the annual chum salmon runs from mid-November to mid-February. Because of the eagles, Brackendale is identified as one of Canada’s Important Bird Areas (IBA). The IBA Program is an international conservation initiative coordinated by BirdLife International with Canadian co-partners Bird Studies Canada and Nature Canada. In 1999, Brackendale Eagles Provincial Park was established to protect 755 hectares of prime habitat for winter roosting and foraging by eagles. Because of our admiration for these great birds, eagle watching has become an important part of the Squamish lifestyle and tourist economy and celebrated through the Eagle Watch program and Eagle Festival.
What is the current status?
Bald eagles flock to the lower reaches of the Squamish River during the mid-winter chum salmon runs. Most of what we know about bald eagles comes from winter counts during this period. Scientific counts of the transitory eagle population likely began with the advent of the awakening of the coastal estuary crisis in the early 1970s but this task was soon overtaken by citizen initiative counts beginning with the annual Christmas Bird Count in Squamish in 1980 and the Brackendale Eagle Festival, sponsored by enigmatic and irrepressible Thor Froslev of Brackendale, in the winter of 1985/86. The Christmas Bird Count at Squamish usually takes place in mid-December, whereas the Brackendale Festival Count is usually in early January.
The data for the 35 years of eagle counting allows some summary observations: eagle counts were low in the period of 1980 to 1985, generally high for 1993 to 2000, and low again in the last eight years (2008 to 2015/16), with one year above-average in 2013/14 (Figure 2). While the numbers are low in the last few years, it does not mean that eagles are disappearing. Eagles are very opportunistic and move elsewhere for their winter food, Harrison River counts have been high in recent years, and in 2016 there was such an unusual abundance at Burns Bog and nearby Fraser River delta that it attracted news media attention. The Brackendale Festival, however, suffered an all-time low of 411 eagles in 2015/16.
Bald eagles are very dependent on chum and coho salmon runs for food during the early and mid-winter when adult eagle mortality is high. When salmon are not available, eagles turn to less favourable prey such as gulls, marine birds, and landfill waste. Climate models for coastal B.C. suggest that flood events in late autumn and early winter due to storms and rain-on-snow events will increase in magnitude and frequency with future climate change. Such increased future floods will pose the risk of larger and more frequent flushing of salmon carcasses to the sea, depriving eagles of important winter food supplies, causing eagles to move from the lower Squamish valley to places with alternative food supplies such as the Fraser delta. Overall, while continental populations of bald eagles may be increasing, their geographic range is gradually shrinking due to habitat loss.
What can you do?
Individual and Organization Actions:
- Learn more about eagles by watching live streaming web cams of eagle nests or by attending Eagle Watch at Brackendale during the winter.
- Use proper viewing ethics when watching eagles. Do not disturb eagles feeding or roosting.
- Know the rules that protect eagles. It is an offense to possess, take, injure, molest, or destroy a bird or its eggs. Eagle nests are protected year round, whether or not the nest is in use, by the B.C. Wildlife Act.
- Adopt the best practices guidelines for protecting eagle nests during development that include identification of eagle nests before development and the establishment of a vegetated no-disturbance buffer zone around the nest tree.
Government Actions and Policy:
- Empower local stewardship by increasing public bald eagle education efforts and education of regulations of the B.C. Wildlife Act, and locations of eagle nests and Important Bird Areas. Increase enforcement of activities restricted in the B.C. Wildlife Act.
- Closely monitor and manage prey species populations, specifically to ensure adequate chum runs are available to support eagle populations.
- Legally recognize and strictly regulate Important Bird Areas as Protected Areas, especially in IBAs that do not have established legal protection (e.g., National and Provincial Parks). Where this is not feasible, consider conservation easements and agreements, private land stewardship, and land acquisition to ensure protection.
- Legislate against the production and use of harmful chemicals (e.g., POPs).