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Bird number estimation practice.

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joehildreth View Drop Down
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Joined: 24 January 2004
Location: United States
Online Status: Offline
Posts: 173
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    Posted: 08 February 2010 at 11:51am
Forwarded from Jerry Jourdan on the MI bird list... great to practice counting large numbers of birds quickly.

All,

I've been playing with Photoshop some more and came up with another
super-panoramic image of the Detroit River at the foot of Southfield Rd. in
Wyandotte (Dingle Park). On the 30th of January there was
a large raft of Canvasback/Redhead Ducks that I photographed using the D300
and 400mm Sigma. I stitched together approximately 30 images to produce
this image: I performed some rough cloning on the top and bottom of the
image to fill in dead space so if it looks
a bit unnatural that's ok.

http://www.pbase.com/jourdaj/image/121761235/original

Now comes the challenge: I'm curious what kind of numbers you folks would
come up w/ trying to guesstimate the numbers of ducks/geese/swans in the
image. Use whatever mental filters you have to get an approximate
number in 60 seconds or so. Please respond off-line if you choose to
participate - I'll summarize results (leaving out names) and report back to
the list.

I tried this and came up w/ a number, which I'll reveal later. I then took
the original, TIFF image I created (805 MB in size), blew it up, and
hand-counted every single bird in the image (don't ask me why....). I was
curious to see how good our perception
is at trying to determine large numbers of birds when we gather census
data. How big is our systematic error? I managed to get 90% accuracy when
I tried it.

Thanks,

Jerry
http://jerryjourdan.blogspot.com

Joe Hildreth 24
Delta, OH
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