[obol] Re: seawatch gull counts
- From: Alan Contreras <acontrer56@xxxxxxxxx>
- To: celata@xxxxxxxxxxxx
- Date: Mon, 27 Oct 2014 17:38:56 -0700
People who don't do ocean watching very often don't realize that huge
percentages of populations move in a short period of time. One year I counted
- pretty closely - ten thousand Surf Scoters *on the water* in one long flock
covering about four miles of the northern Lane County coast. The movement had
chosen to rest there. They looked like the world's largest kelp string - but
they were all Surf Scoters. And I mean zero White-wings. In two days they were
gone. Cal Gull, Pacific Loon and, in spring, Western Sandpiper do the same
thing, though the gulls are a bit more spread out.
.
.
Alan Contreras
acontrer56@xxxxxxxxx
Eugene, Oregon
On Oct 27, 2014, at 5:32 PM, Mike Patterson wrote:
> We shorted many of our numbers, because they seemed so overwhelmingly
> large. In my notes for Sunday, wrote rates rather than try to keep
> an actual count. We counted for 2.5 hours, so the math is:
>
> (Count/min)*60*2.5 = number encountered during watch
>
> From that I got:
>
> California Gulls 100*60*2.5 = 15000 (5000 reported)
> Northern Fulmar 10*60*2.5 = 1500 (300 reported)
> Pacific Loons 80*60*2.5 = 12000 (8000 reported)
>
> I always hesitate reporting math based values, in part because the
> rate is not uniform over the morning and making enough rate counts
> over a morning to be statistically robust requires not paying attention
> to all the lower frequency action which is often way more interesting.
> But I've also had folks argue with the big numbers, usually folks
> who've not witnessed these kinds of events, who think I'm being over
> dramatic. So I habitually trim them.
>
> But given all the supporting data from other locations, I may go back
> into the eBird list and fix these (eBird filters don't like these big
> numbers either).
>
> --
> Mike Patterson
> Astoria, OR
> String Theory
> http://www.surfbirds.com/community-blogs/northcoastdiaries/?p=2182
>
>
>
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