Development of Bald Eagle Etiquette for the Chehalis Flats – Harrison Mills.

Prepared for the ‘coalition of the concerned’ – by the Chehalis Flats Bald Eagle & Salmon Preserve Committee.      This document is to be constantly updated by the various ecologically  concerned groups:  the Sts’ailes First Nations,  the Harrison Mills Regional Association, the Fraser Valley Bald Eagle Festival Committee, the Salmon Stronghold  and the Hancock Wildlife Foundation.            Feb 13, 2013

Background of Chehalis Flats Bald Eagle & Salmon Preserve Concerns:

Sts’ailes local name for Chehalis Bald Eagle & Salmon Preserve is Lhá:lt

The Fraser Valley Bald Eagle Festival has promoted the presence of bald eagles in the Harrison Mills area for nearly 20 years.  Most recently David Hancock reviewed various bald eagle winter concentration areas in British Columbia and Alaska.  The historic evidence clearly shows that bald eagles frequent many spawning rivers throughout the northwest, with large numbers recorded at specific sites like the Chilkat River in Alaska, the Squamish River near Brackendale BC and the Harrison River, a tributary of the lower Fraser River of British Columbia.  Just upstream along the Harrison is the alluvial fan forming the Chehalis Flats where the largest concentrations of bald eagles in the world have been recorded. This same river flats is designated part of the first Salmon Stronghold, to signify this is Canada’s most productive river ecosystem. This area is special and deserves special attention.

The reasons for these eagle movements and the huge gatherings of eagles on the Chehalis Flats in southern British Columbia are largely two-fold:  weather conditions up north and salmon availability for the eagles throughout the area.  The food availability locally is driven by the incredible productivity of the Harrison River system salmon runs.  Historically we have seen that just having lots of spawned out carcasses does in itself not bring record numbers of eagles.  Normally the wintering eagles are dispersed all along the northwest coastal salmon rivers, feasting on the carcasses until they are eaten out or frozen under the ice. As this food source disappears under the ice or is eaten out, the eagles move south.   On top of the influence of weather conditions is the actual numbers of salmon actually returning to the different rivers each season.  Fewer spawned-out salmon in the northern rivers simply means, regardless of impacting weather, that less poundage of salmon are there to feed eagles – or bears, gulls, wolves etc.  With fewer spawning carcasses to the north, the eagles come south to the Chehalis Flats.

The past 15 years of gradual build-up in numbers of wintering eagles at Harrison Mills seem to be related to a decline in other spawning salmon populations in northern rivers – and of course due to the increasing numbers of eagles.  Then in 2010 we had a world record for a gathering of eagles.  David Hancock counted individually 7362 eagles in a 3 kilometer section of the Chehalis Flats and probably several thousand more existed in the trees, soaring and spread southward to Harrison Bay (Hancock D above).  This is almost twice the size of any earlier recorded gathering of eagles anywhere in the world.

The point to be made here is that our big numbers of eagles here are likely the result of the collapse of most of the northern runs of chum salmon in the fall of 2010.  We are simply at the southern end of their potential migration and with fewer salmon carcasses to the north the eagles kept coming south.  We greeted them, and they depend upon, the food resource of the Chehalis Flats,   Canada’s most productive salmon river.

The importance of the fish and the Chehalis Flats alluvial fan are increasingly important to bald eagles.  The flats are the southern most of the large salmon spawning areas and do not just offer one of the last great feasting areas for the eagles before nesting but an important resting and socializing place for the eagles to build up reserves for winter.   As might be expected the Harrison Mills area also hosts the world’s largest known eagle night roost:  the cirque of hills and ancient lowland forest of cedar and Douglas fir surrounding Echo Lake, one kilometer west of the Chehalis Flats.  Each night and morning the eagles can be seen entering and leaving this ancient roost site.  All the large forest surrounding the Chehalis—Harrison complex serve as day and night roosts for bald eagles in good weather.

The Chehalis Flats cut with the channels for spawning salmon, the surrounding shorelines of giant cottonwoods, the hills along both sides of the Harrison Valley from Mt. Woodside on the east to the Echo Lake cirque and night roost to the west, constitute one of the world’s greatest bald eagle wintering habitats known.  The salmon flats of the Chehalis that feed these wintering eagles is a national treasure that needs protecting.

The Salmon Concerns:   Undoubtedly an even bigger issue justifying the preservation of the Chehalis Flats is the welfare of the vast diversity of spawning salmon and the year-round sensitivity of spawning and rearing habitats utilized by these salmon population.  The Harrison River and its tributaries have recently been proclaimed Canada’s most important salmon river and been designated the first Salmon Stronghold in Canada.   The aim of the Salmon Stronghold is to preserve the total biological diversity that characterizes this area as one of the most productive rivers in the Pacific Northwest.

All 5 species of salmon spawn in this ecosystem along with steelhead, rainbow and cutthroat trout as well as bull trout and a variety of other species that depend upon them for food or share their habitat. Adult salmon, their eggs and fry are present throughout the Chehalis Flats and the adjacent gravel beds every month of the year, and then the juvenile salmon move into the tributaries, river margins and wetlands where some may reside for more than a year after that – growing and feeding other wildlife before finally swimming downstream and into the Salish Sea for the next phase of their lives.

Most importantly, some of these fish are present in the river gravels during the time when the water is low and the eagles are present on the Chehalis Flats.  This is the time of spawning, digging of the redds, the hatching of the delicate yolk sacked fry (alevin) which are particularly sensitive to disruption by foot traffic and shallow operating boats.  Well meaning observers on foot or in a boat may inadvertently disrupt incubating fish in an effort to move closer to observe the activities of eagles, spawning salmon or waterfowl.  We need to keep unnecessary disturbance on the flats to a minimum.

Unique Salmon Challenge:   Salmon that spawn on the Chehalis Flats are particularly susceptible to foot and boat traffic.  Spawners have keyed in on the choice gravels and wetlands, loosened and fed by Harrison Lake runoff and warm groundwater-fed aquifers that still provide flow in late winter. Many juvenile salmon fry will remain in the gravel until late March, their presence obscured by surface gravels that belies their busy life just beneath the surface while they await the spring freshet to carry them free. The goal of the Chehalis preserve for salmon is to ensure that foot and boat traffic on the soft wetland gravels is minimized after spawning and until inundated with sufficient freshet flows in the spring.

 The Bald Eagle Concerns:  The incredible gathering of bald eagles during each fall and winter need not just food.  They need peace and quiet and rest.  A bioenergetics study done 20 years ago showed that bald eagles cannot sustain their body weight, no matter how much they eat in a day, if they have to undertake wing-flapping flight for more than 28 minutes a day.  They can soar almost effortlessly for many hours, in fact soar and glide for hundreds of miles a day.  But the challenge for this large scavenger – predator is to eat and rest and socialize.  The flats are the world’s great feeding and resting grounds for the eagles.   We need to not disturb them or the spawning salmon on these flats.

The purpose of Chehalis Flats Bald Eagle & Salmon Preserveis to initiate some program to reduce human disturbance to the loafing eagles out on the flats and protect the shallow waters with eggs and fry from constantly being trodden upon by people, motors and disruptive wakes.   From the eagles’ and salmon’s perspective, we see no problem at all with boat, kayak or fisherman traffic along the Harrison River main channel or humans walking along the commercial developments bordering the west shoreline.  These areas have large trees to let the eagles sit securely, well above the passing humans below. They have no shallow gravel beds in which eggs or fish are disturbed.

The Chehalis Flats Bald Eagle & Salmon Preserve is Born:

I have to admit that the “disturbance concerns” have been talked about for some years by local residents.  However, until I and others saw, via our live streaming eagle cams, that show the constant human access to the flats and shallow waters and the repeated disturbance to the fish and feeding and loafing eagles, I was not as fully aware of the problem. These cams could also serve in the future to not just be an educational tool for the benefit of the eagles, salmon and the other wildlife but as surveillance and monitoring tools for violations.

The disturbances are caused by many kinds of intruders. When the water is higher the motor boats, jet skies and joy riders disturb the shallow waters.  As the Flats dry out the most frequent and disruptive activities are the kayakers and walkers.  Some have even posted blogs that say how they got away from jet boaters on the deep river channel by accessing the flats to flush the eagles for good close-up photos of the flying birds!  Indeed!  On one day, when the water was a little higher, we had Sea-Doos, helicopters, jet boats and punting hunters out on the flats;  dog walkers, off-road bikers,  4wheelers and cameramen with long conspicuous lens and fisherman add to the constant invasion of these spawning waters and the eagle feeding and resting areas.  More respect for this international ecological treasure is needed.

The Preserve Campaign:  It may well be that a campaign that targets the education of the outdoor sports clubs, the fishermen and hunters and the camera buffs, supplemented by posters at each launch or water access site would go a long way to solving this issue.  I suspect those wishing to view the glory of our nature wish to do so in a way that is not as totally disruptive as is happening. Perhaps this educational campaign will do its job.   The salmon, the eagles – the ecosystem – needs more peace and respect.   Some Chehalis Flats conservation etiquette awareness may be all that is needed.  Some stronger words in access regulations may be needed or considered.


David Hancock,   Eagle Biologist

Hancock Wildlife Foundation, Director Fraser Valley Bald Eagle Festival.

Dave Moore,   Fisheries Technician and General Manager

Harrison Fisheries Authority

Kim Charlie, Fisheries Biologist,   Sts’ailes First Nations.


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