Thanks John. It's not easy and it's one of those things
where if you don't have any measure of your estimates you don't get any
better. I'm sure that the experts mentioned by Dan learnt from the experienced
estimates of others. Photos might have helped.
I'm not too good myself and I won't go on and on, but
here are exactly 100 waders:
-----Original Message-----
From: John Brannan [
Sent: Thursday, 18 March 2010 2:36 PM
To: Geoffrey Dabb
Cc:
Subject: Estimating numbers
Geoffrey,
Thank you very much for this. It was highly instructive.
My own hesitant
initial estimate was 60-70 birds - serious undercounting,
as it turns out.
In future, I wonder whether it might be helpful if, when
counting
smaller numbers (20 or so) where counting of individuals
is feasible,
one were to take a step back after the count, take a
fresh look at the
group and say to oneself, "Right. That's what 20
birds looks like."
John Brannan
Geoffrey Dabb wrote:
>
> Very interesting. Estimates mentioned to me ranged
from a wary ‘0 –
> not starlings’ to ‘200-300’. It might or might not
be helpful if I
> told you that each of the first 4 coloured sections
represents 50 birds:
>
>
>
>
> I would think that very few people would know,
intuitively, what 200
> birds ‘looks like’. Barbara P mentioned the
semi-counting method of
> counting 10 - then counting the number of tens.
That depends on
> having the flock in view for long enough. John
Rawsthorne – an old
> sheep-counter like a few others – said if it looks
like 100 it’s
> probably twice that number. That is, in a way,
knowing what 200
> ‘looks like’ - it looks like 100. That kind of
knowledge comes from
> knowing at some stage the actual number of estimated
quantities, so
> perhaps the sheep counters have an advantage.
>
>
>
*******************************************************************************************************
This is the email announcement and discussion list of the
Canberra Ornithologists Group.
Please ensure that emails posted to the list are less
than 100 kb in size.
List-Post:
<>
List-Help:
<>
List-Unsubscribe:
<>
List-Subscribe:
<>
List archive:
<http://bioacoustics.cse.unsw.edu.au/archives/html/canberrabirds>
List manager: David McDonald, email
<>
