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Thank you Larry and Mona for the Finnish/Danish count site. It kind of 
confirms what I had thought all along, that my counts , at least on larger 
flocks of birds, was under their true number. And that is OK. Subconsciously 
I think many counters worry (especially when counting alone) their number 
will be too high to be believed or will be questioned. Another reason may be 
a subconscious line of thinking that if a person reports high numbers it 
will appear that the species is doing better than it may if fact be. Thus a 
conservative approach to counts. It is totally correct that 10 birders 
counting a flock of 121 birds as they fly by will have 10 different amounts.

To suggest a few reasons why or how when counts for a CBC seem to get 
several people to agree to an exact number, I offer:
I think if there is one member of the group who the others feel is the more 
experienced (a"better" birder, don't necessary like that description) then 
the others in the group will defer to that person's count.
If there is a small group of 3 or 4 experienced birders then I think they 
kind of reach a consensus even though they each may have a slightly 
different count. And if the flock size is under a hundred birds, I think 
they go with the person who had the higher count. I think these count 
scenarios can get pretty accurate .

After playing  the "count game" twice my estimates were off by sometimes 200 
birds under on a 600 bird flock. Not very good estimating! But at least not 
over estimating. On the third try I intentionally tried to estimate higher 
and on a few wound up being over by a hundred. Surprisingly on one flock my 
estimate of 624 birds was exactly correct 624 birds! Pure luck!

Tom Berriman


----- Original Message ----- 
From: "Larry and Mona Rogers" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, February 05, 2011 9:18 AM
Subject: [VTBIRD] Counting Birds


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>    Much of what has been written on this topic makes sense.    We all =
> try to do the best we can. =20
>    There was an article in one of the birding magazines about ten years =
> ago which described an interesting experiment.  Using a large enclosed =
> aviary, experienced birders were told to go inside for a measured amount =
> of time and produce an estimate of the number of each species present.  =
> This was an aviary which had a large bird population - 25 birds of some =
> species, 50 of others, etc.  If we remember rightly, species counts were =
> consistently low (circa 60% - to 70%), and longer time periods did not =
> improve count accuracy appreciably.
>    You can improve your flock size estimation skills with practice.  =
> Try the Finnish/Danish bird counting game at
>
>            http://personal.inet.fi/cool/live/birds/index.html.
>
>
>    With all of this said, we are always amused at the apparent =
> precision of some reported counts.  During Christmas Bird Counts for =
> instance, a group of observers will see a large flock of starlings in a =
> farmyard and agree on a count of 120 individual birds.  Later the same =
> group will see a flock of starlings flying overhead and agree that it =
> contains 45 birds.  Still later they'll see 4 starlings at a feeder and =
> 3 more on the ground somewhere else.  At the end of the day, they will =
> report that they have seen 172  (120+45+4+3) starlings.  This count will =
> be added to that of several other teams to come up with a very precise =
> sounding total.  We don't know what the answer to this is; perhaps one =
> of our more professional ornithologists would like to weigh in.
>    Larry and Mona


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