Dear Chuck and Bob,
From my perspective, the number of GREAT EGRETS wintering in northwestern
Oregon has dramatically increased over the past 25 years. I just went back and
pulled the Tillamook CBC data for Great Egret going back to 1980. Between 1980
and 1985 no Great Egrets were reported on that count. Between 1986 and 1989
either one or two Great Egrets were reported each count. Between 1990 and 1997
an average of 9.1 Great Egrets were reported on that count per year. Between
1998 and 2003 an average of 17.1 Great Egrets were reported on that count per
year. Between 2004 and 2014 an average of 49.8 Great Egrets were reported on
that count per year. I did a similar analysis for the Portland CBC. Between
1980 and 1991 there was only one Great Egret seen on the Portland CBC and that
was in 1981. Between 1992 and 2000 Great Egrets were seen on all but one count
with a high of 63 in 1997. The average during that period was 11.8 per year.
If you exclude the spike in 1997, the average during that period was 4.4 per
year. Between 2001 and 2014 the average during that period was 7.7 per year.
I also looked at the Sauvie Island CBC data for Great Egret going back to 1980.
Between 1980 and 1990 an average of 3.9 Great Egrets were reported on that
count per year. Between 1991 and 1998 an average of 17.9 Great Egrets were
reported on that count per year. Between 1999 and 2001 an average of 59.3
Great Egrets were reported on that count per year. Between 2002 and 2005 an
average of 155.8 Great Egrets were reported on that count per year. There is
no data for the Sauvie Island CBC between 2006 and 2014. I suspect that
analysis of CBC data for other counts in northwestern Oregon will show a
similar pattern of increasing numbers of Great Egrets between 1980 and 2014.
The CBC data is consistent with my personal observations over that period of
time.
Sincerely,
Tim Janzen
From: obol-bounce@xxxxxxxxxxxxx [mailto:obol-bounce@xxxxxxxxxxxxx] On Behalf Of ;
Charles Gates
Sent: Saturday, March 19, 2016 9:49 AM
To: obol@xxxxxxxxxxxxx
Subject: [obol] Re: clackamas co egrets
As an out-of-the-area birder, I find this thread interesting. Smith-Bybee is
not very far from Clackamas County by my reckoning and it gets dozens of
egrets. I'm surprised that places along the Clackamas River like Barton Park
or some of the farm fields out that way don't occasionally get flocks of
egrets. There seems to be a lot of open area around the confluence of the
Clackamas and Willamette Rivers that would be ideal for egret flocks after a
good week of rain.
On 3/19/2016 7:10 AM, Robert O'Brien wrote:
Interesting. Several were reported from sauvie is. Yesterday. I wonder if
they are coming north? Do they winter on sauvie is?
