Monday, October 21 2013 @ 05:59 PM EDT
Contributed by: davidh
Christian Sasse and I for the past couple of years have planned on a systematic methodology of counting the eagles at the Harrison River. My former counts for the official Fraser Valley Bald Eagle Festival counts were done from 6 set locations from Harrison Bay around past the Highway 7 bridge northward up Morris Valley Road to Tapadera RV Estates. I have made these counts for many years and sometimes from the date of the Festival on through the winter and we will work to replicating this information -- but with photographic verification and accuracy.
While my above counts were always 'counts' and not estimates, they were always far under the actual number of birds present. Some birds were simply in the 'dips' below sight and others sitting on the backside of trees. This difficulty also applies to counting birds with the camera but the higher resolution leaves less doubt -- a head can be verified as an eagle! Furthermore, because my telescope did not have sufficient resolution to differentiate the juveniles on the far side of the river, 1.5 to 2.5 km. away, I was also missing them and under-counting. Many of these juveniles are seen with the high res camera. Last year we experimented with a motorized camera mount and high resolution lens. This year Christian Sasse has improved the resolution of his equipment and we should be able to distinguish even juveniles across the flats.
This year we may also incorporate a new counting position in the north-east section of the Flats. This count will come from cooperation with the Fraser River Safari boat tours that enable us to access the eagles on the east side of the Harrison River, north of what can be seen from the eagle observatories.
Attached is his first shot of the year, taken Oct. 20, 2013, 7:54 AM. This test shot does not even cover all the Chehalis Flats and of course does not cover any of the other advantage points of the official count. However, yesterday we already had 443 eagles visible at one time on the northern section of the Chehalis Flats. Our eagles are coming south!
Minutes ago in discussions with Christian he mentioned that soon he will present the composite images with grid lines to facilitate counting. We will set up a Table for Counts and Locations with dates so others can follow the arrival - and departure -- of the eagles -- and possibly the trumpeter swans as well.
This Harrison River Bald Eagle & Trumpeter Swan Counts Table will be posted on the Hancock Wildlife Foundation site and periodically updated. The table will be accompanied by a map of the sites and the arc viewed from each location. We will distribute the url so you can get the updated counts. By keeping the official count at one site you will get frequently updated counts as the season progresses.
Attached for your reference is the url to Christian Sasse's first photograph.