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Prepared for the ‘coalition of the concerned’ – The Chehalis Flats Protection Group!     

Nov. 20, 2012    Updated Dec. 6, 2012

By David Hancock,     Bald Eagle Biologist,    Hancock Wildlife Foundation.

 Background of Chehalis Flats Bald Eagle & Fish Concerns: 

Fraser Valley Bald Eagle Festival for 20 years and in the past 7 years the Hancock Wildlife Foundation  have promoted the presence of bald eagles in the Harrison Mills area.  Most recently David Hancock reviewed various bald eagle winter concentration areas in British Columbia and Alaska and other North American sites.  The historic evidence clearly shows that over time many different areas hold varying numbers of wintering eagles.  The region’s largest concentrations have regularly been at the Chilkat River in Alaska and the Squamish River system near Brackendale, BC.  More recently the Chehalis – Harrison River complex in Harrison Mills has wintered the largest concentrations ever known.  

The reasons for these huge gatherings of eagles 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.   On top of the influence of weather conditions is the prime numbers of salmon actually returning to the different rivers to spawn 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 the next generation & Fish.


The past 15 years of gradual build-up in numbers of wintering eagles at Harrison Mills seems to be related to the general loss of spawning salmon in northern rivers – and of course due to the increasing eagle population.  Then in 2010 we had a world record for a gathering of eagles.  I counted individually 7362 eagles in a 3 kilometer section of the Chehalis Flats and probably several thousand more existed in the trees, sitting in the channel bottoms out of sight, soaring and spread southward to Harrison Bay.  This is almost twice the size of any earlier recorded gathering anywhere.  The point I wish to make here is that I suspect our big numbers of eagles here were the result of the collapse of most of the northern runs of chum salmon in the  fall of 2010 – from here northward throughout SE Alaska.  We were simply at the southern end of the eagle’s potential migration — dispersal pattern.  With fewer salmon carcasses to the north the eagles kept coming south.  We greeted them with our excellent Coho run.

The 2010 build-up of eagles from early November through mid-December lasted until the Coho and small chum salmon runs were eaten out.  A week later, with the carcasses eaten up, the eagles left. 

The importance of the fish nutrient cycle and the Chehalis Flats alluvial fan are increasingly important to spawning salmon and bald eagles.  The flats are the southern most of the large west coast salmon spawning areas and not just offer one of the last great feasting areas for the eagles before nesting but are an important resting and socializing place for the eagles to build up reserves for winter.  This population of eagles is undoubtedly made up of juveniles and adults from our southern British Columbia and Washington State breeders and their young as well as northern breeders.  After abandoning the young at the end of July our southern eagles migrated north to northern BC or SE Alaska.  By October thru December they are returning south having just completed a 1500 to 3000 mile journey.  They need to feed and to rest.  These Chehalis Flats need to give that feeding and resting opportunity.

 As might be expected the Harrison Mills area also hosts the world’s largest known 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 hundreds of eagles can be seen entering and leaving this ancient roost site.  We are simultaneously trying to have the last 49 hectares of this Ancient Forest and night roost protected from logging.  See the Ancient Forest Alliance story.

Also as hinted above, the Chehalis – Harrison River system is incredibly rich and still runs almost devoid of farming, mining, industrial waste or over logging negative pressures.  We have what was recently defined as the most important salmonid river in Canada – right here in Vancouver’s back yard.   Several major international conservation organizations have designated the Harrison – Chehalis River Complex the first Salmon Stronghold in Canada.  A committee has been struck to oversee this river’s continued success.  This committee is hosted by Chief Willie Charlie of the Sts’ailes First Nations Band, a people who have lived continuously on these lands for over 6400 years, and most participants are fisheries habitat restoration biologists.  Some of us were invited to speak for eagles.  

We have also been invited to contribute to the upcoming Vision Conference to set the Stronghold’s goals and objectives for the future. We will be focusing on how the public and Sts’ailes First Nations can utilize the wondrous concentrations of spawning fish and gathering eagles to excite and educate the public, how specifically our series of live streaming cams can advance research and educational opportunities, and specifically how the Harrison Salmon Stronghold can bring economic opportunities to the local businesses and the First Nations peoples.  We will be developing this Vision in the coming months and look forward to participating in that conference.  In the meantime we are inviting the fish ecology and stream keeper community to contribute to our web forums attached to our Underwater cams or import these streams to your sites for discussion.

The story of ecology, the interactions of inorganic, organic and more recently the human-imposed changes on water happens in each of the world’s drainage systems is nowhere more important and more under the scrutiny of prying eyes than here on the Harrison – Chehalis system.  This close inspection is important but brings with it some additionally and timely imposed responsibilities.  The Sts’ailes continuous occupation of this valley speaks to their understanding of the importance of the Chehalis habitat cycle. 

Our Fraser Valley Bald Eagle Festival promotional efforts have been focused on drawing to the public’s attention the importance of this cycle through the presence of the spectacular eagle concentrations.  More recently the Hancock Wildlife Foundation, by inserting live streaming cams into the Chehalis River to view the salmon, placing two Tower cams in the centre of the Chehalis Flats to view thousands of wintering eagles feeding, squabbling and resting and by installing several cams in bald eagle nests along the Chehalis (the Harrison Mills nest!) and other Fraser Valley bald eagle nests, has collectively increased the public awareness of this extraordinary world-class wildlife event on the doorsteps of Vancouver.

But there is a possible downside — well really more of a ‘catch-up’ side.  Have we attracted so many people that we are in danger of ‘loving the eagles to death?  I don’t really think this for the moment but we do need to be aware of human presence and advising the unwary public that some kinds of disturbance to the Chehalis Flats is not good for the ecology – the fish or the eagles. We have now arrived at that challenge and this proposal and the meeting that we just undertook yesterday will start to establish some ethical – ecological guidelines on how the most vulnerable parts of this Chehalis Flats habitat can best be preserved.  The group’s first meeting drew a unanimous conclusion.  We will approach the ‘big- picture’ ecology of the Harrison – Chehalis System and associated key attached elements like the Echo Lake Ancient Forest Night Roost on specific and already underway legal paths.  The very tiny central Chehalis Flats, where fish habitat and feeding and loafing eagles need special attention, would be undertaken immediately.  This special habitat is already under some specific landowner, local and Provincial protections and we will use these elements to preserve the special central flats where to fish and eagles need to be left alone.

The Chehalis Flats Preserve Group will meet this coming week and set up some guideline for seeking broader community involvement with the different groups and development of an educational program aimed to inform the various groups who utilize the Chehalis Flats by providing some seasonal guidelines needed to protect the fish and eagles.  The Fraser Valley Bald Eagle Festival already committed $2000 to the production of signage to be placed at the various River access points.

Our live streaming cams, which are of course ‘security cams’ that Pan-Tilt-Zoom to cover the entire area,  have already documented the great variety of intruders and how the eagles are almost constantly harassed.   Most of these are people wishing to enjoy the closeness of fish and eagles.  They simply have not understood that their presence, which drives off the eagles from their feeding and resting perches, is a major illegal disturbance of these creatures – and a major disruption of this important but short–lived feeding and loafing opportunity after a 2000 to 3000 mile journey.  We believe none of these groups will oppose the safeguards of the flats once they are aware of the issues. Simply education is needed.

In summary, the Chehalis Flats river channels are the prime spawning salmon habitat and the feeding and loafing grounds for the world’s largest gathering of bald eagles.  The surrounding shorelines of 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, collectively constitute the world’s greatest bald eagle wintering habitats known.  This site deserves more protective concern than it is presently getting.

The Big Concern:   The incredible gathering of bald eagles during each fall and winter needs 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 build up body weight for hungry days.  The flats are the greatest feeding and resting grounds in the entire world for the bald eagle.  We need to not disturb them on these flats.

The purpose of this note to the proposed ‘gathering of the concerned’ is to initiate some program to reduce human disturbance to the feeding and loafing eagles out on the flats.  From the eagles’ perspective, I 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.

I have to admit that the “disturbance concerns” have been talked about for some years by Kathy S and Tom C.  However, until I saw, via our live streaming cams, the reality of this constant disturbance I did not realize its magnitude.  The cams show the eagles and the constant flow of human access to the flats and the repeated disturbance to their feeding and loafing eagles.  Our camera moderators have created a file of these disturbances should they be needed.  These cams could also serve in the future to not just be an educational tool for the benefit of eagles and fish, but as surveillance and monitoring tools for disturbance.

The disturbances are caused by many kinds of intruders but the most frequent and disruptive are the kayakers.  Some have even posted blogs that say how they got away from jet boaters on the deeper channels 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, cameramen with long conspicuous lenses and fisherman add to the constant invasion of these eagle feeding and resting areas.   

Our group has agreed that it may well be that a campaign that targets 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.  Many of the landowners of the flats and the adjacent lands already have legal access or hunting restrictions in place.   Let’s hope that an educational program to our outdoor and nature enthusiasts simply makes them aware of this import resource and the need for some seasonal non-access non-disturbance etiquette.

David Hancock,   Eagle Biologist

Hancock Wildlife Foundation, Director Fraser Valley Bald Eagle Festival.  Member of the Chehalis Flats Preservation Group and the Harrison Salmon Stronghold.