Paul, very interesting results for a species for which subscribers may be
aware I have a special interest.
My initial reaction was that as an urban rather than a rural species the GBS
survey data should show bigger increases in numbers than the general survey.
However, you are (de facto) showing a percentage increase, and so a small
increase in numbers on a small base may be the same as a larger increase in
numbers on a much larger base.
However, as the oil companies are fond of saying, it's not that simple. The
above ignores the fact that, at least for me, many of my observations going
into the COG database are into the general surveys as ad hoc records - this
is true for both the fledglings and the adults that often associate with
them. For example, this breeding season I actually only had one record of
two birds in one week in my GBS site for the whole of the spring/summer,
whereas over several months I found 2 fledglings separately as well as up to
five adults together outside of my GBS site but within 500 metres of my
house.
So that the 2 graphs are virtually identical is remarkable. Most people
would probably agree numbers are increasing, though ironically I had a much
quieter koel season in my local patch this year than for the two previous
spring/summers.
Jack Holland
-----Original Message-----
From: Paul Fennell
Sent: Thursday, April 07, 2016 2:31 PM
To: Canberrabirds
Subject: Eastern Koel
Hello everyone
I hope we are all getting more sleep now that most if not all the Eastern
Koels have gone back east. At least the Pickles Street crowd have left.
In writing up the Highlights and Lowlights section of the Annual Bird
Report, I have been debating whether the increase in Koels in the ACT is a
highlight or a lowlight.
I have attached a short statement about their increasing prevalence which
contains a couple of graphs. Unfortunately I am not sure how to include
graphs in email texts with this new iMac system I have, since all I get is a
box with a question mark in it. Thus the resort to including an attached
word doc with the graphs in there.
I would be interested to hear what people think.
Paul Fennell
Editor, COG Annual Bird Report
0407105460
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