Hi all,
In tandem with the National Audubon report, Audubon Ohio also released a
list of the top 20 species that have declined in Ohio. Another interesting
compilation. I've posted it over at the Ohio Birds Forum, which is a better
place to accommodate an open-ended discussion like this. Have a look at the
list, and share your thoughts.
http://www.ohiobirds.org/forum/viewtopic.php?pid=1123#p1123
Jim McCormac
Columbus, Ohio
-----Original Message-----
From: Ohio birds [mailto:[log in to unmask]] On Behalf Of Bob
Powell
Sent: Sunday, June 17, 2007 1:57 PM
To: [log in to unmask]
Subject: Re: [Ohio-birds] Audubon "Birds in Decline" report
On 6/17/07, Bill Whan <[log in to unmask]> wrote:
>
> Guess nobody had any thoughts to share on Audubon's lists of birds in
> decline.
>
Well, I was going to reserve my comments until I have read the full report,
but the demands of atlassing may mean that it will be sometime in late July
before that happens. In the meantime, here are a few first impressions.
1. The Christmas counts and the breeding bird surveys are strike me as
very blunt instruments for producing continental population estimates no
matter how sophisticated the statistics are. The sampling issues alone
would be enough to shoot down the conclusions. The CBCs are also
notorious
for their lack of uniformity of level of effort. Some are done by one
observer, some by 300. Neither have any standardization or training for
the
observers.
2. There seems to be little or no compensation for covariates, such as
the changes in land cover and land use, changes in weather patterns, etc.
There seems to have been little use of the wealth of GIS and remote
sensing
data out there.
3. No confidence intervals are given. I recently attended a workshop
on distance sampling in which two regional (not continental) population
estimation studies were presented. Both were done with the latest and
greatest techniques for compensating for the probability of detection and
both were done with excellent stratified random samples. In both cases
the
confidence intervals were huge. Both of them concluded that in order to
detect a significant population change with good accuracy would require
replicating the surveys every year for about 20 years.
4. I am skeptical of the mesh on the time scale. From the New York
Times account it sounds as if their trend analysis is conducted on just
two
data points separated by 30-40 years. That misses out a lot of
structure.
5. I note that the report was not properly peer-reviewed. By
self-publishing, NAS has done an end run around that process, though they
claim to have had some sort of private peer review. No fair.
6. By going big with a poorly-designed study, NAS may be doing more
harm than good. Those who oppose conservation measures will have been
given
more material with which their hired biostitutes can assail environmental
groups for pushing "poor science." I am a veteran of two such campaigns
(Prince William Sound and the Everglades) when we came under heavy fire
from
special interests when the science was actually outstanding, as
subsequently
proven by peer review.
But as I said, I haven't read the report yet.
Cheers,
Bob
--
Robert D Powell
Wilmington, OH, USA
[log in to unmask]
http://rdp1710.wordpress.com
Nulla dies sine linea
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Our thanks to Miami University for hosting this mailing list.
Additional discussions can be found in our forums, at www.ohiobirds.org/forum/.
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