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May I
remind everyone that the USE of the garden is explicitly not a criterion for counting for the GBS. Mainly because to
do so simply creates confusion (or different opinions) between people, as to
what constitutes "use". The criterion is only a detected and identified presence
within the designated part of geography, within the time period. See this part
of the instructions, that has been on every chart since 1993:
Instructions for Filling in the Garden Bird Survey
Chart:
·
Write your name and identifiers in
the white boxes. The starting day for each week is listed at the top of the
chart. For convenience, write the day matching those dates in the white box. In
leap years, week nine has eight days, then the starting day changes to one day
later. If you make no observations for a particular week, clearly cross out that
week number and date at the top and leave the column blank. Decide on, and keep
to, a survey area equivalent to a 100 metre radius (3.1 hectares) from
house/work and include only observations from within or over this area. There is no altitude limit, and no
requirement for the birds to be 'using' the area.
·
For each species observed (heard or
seen), record the maximum numbers of individuals occurring in the area at any
one time within that week. When you do not know the actual number, record your
best estimate, do not leave the record blank. At the end of each week, work down
the chart so as not to miss out species. Only write one number and breeding
code, no zeros, ticks, dashes etc., please. List
additional species using their standard names in the spaces provided. Submit any
rarities forms promptly.
As for the Myna e.g. I agree with everyone else, mostly probably with
Julian. In Paul's question, if that is the only bird, the answer is clearly
1. Also note there are no zeros included as counts in the GBS.
I think the bigger question is if you have
for example 15 Mynas in a trap and then 30 enter your garden, should the GBS
number be 30 or 45? In that case the issue is does the restraint of the 15
influence the presence of the 30? If on the best of the observer's
ability to detect, the mynas were free before being trapped at the time the
other counted mynas were also in the GBS area, then you would count them all. If
not, maybe it is biased, to record 45, rather than 30, because the 15 birds that
were trapped means that it artificially allows or even attracts additional birds
in the area. Just in the same way that you don't add the number of migrating
honeyeaters that were in the area one minute earlier to the number come in in
the next flock. In every case however I
suggest that there is likely to be many more birds in your GBS area (3.1
hectares) than what you detect in your own garden, so the true numbers are often
more than what is observed.
In the end, I don't think it matters a huge
amount what the precise answer is. The numbers get pooled and averaged and a
count up or down by a small number either way is not a big issue. Far more
important that we get as much coverage as possible from more
contributors from more suburbs. I would not like little questions like this
to put off people from contributing because they think it is too hard.
I am reminded that about a year ago I wrote
a similar question about being at Kambah Pool and seeing someone release a Red
Wattlebird he had caught raiding his fruit trees. As I did not record any other
Red Wattlebird at that site that day and if I had not seen the man open the box
and the bird fly out, I would not have known how it got there. I asked
'canberrabirds chatline' should I record it. I got inconsistent answers to that
one too - and as I recall I did not put in any record sheet.
Philip
The
count is about the birds that use your garden. Birds can use a garden in
all sorts of ways. If it happens to use it to die then it still gets
counted.
Chris
From: Sue
Lashko [
Sent: Sunday, 2 June 2013 9:55
AM
To: Paul Fennell; canberrabirds chatline
Subject: Re:
[canberrabirds] Counting C Myna in GBS
It was alive and in the GBS when trapped - no different from
you seeing a bird in the GBS and then the cat eating it!
On Sun, Jun 2, 2013 at 9:44 AM, Paul Fennell <>
wrote:
Hi everyone
To me, this is akin to Schrödinger’s cat, but with a practical
aspect.
I one traps a Myna bird and disposes of it. Does it appear
on the GBS Chart as a one or a zero?
Cheers
Paul
Paul Fennell
Editor Annual Bird Report
COG Databases Manager
026254 1804
0407105460
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