[TN-Bird] Re: species apparently in decline (BBS data)
- From: OLCOOT1@xxxxxxx
- To: tn-bird@xxxxxxxxxxxxx, cpnichol@xxxxxxxxxxxxx
- Date: Tue, 1 Apr 2003 10:04:56 EST
Thanks, Chuck for a reply.
But, it seems to verify some things and then mix them with others. I have
received quite a few replies off line from BBS surveyors that fear to shoot
at a sacred cow in public and I under stand their concerns. Also I might add
that before I posted the question I had spent considerable time at the BBS
web site that Troy Ettle wrote about. I recommend others do the same. It just
raised a lot of questions for this layman.
Playing the devils advocate here.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
In short, the numbers are not adjusted, either a priori or post priori, to
account for habitat changes along routes.The changes in bird populations
resulting from change in habitat along the routes (as well as changes in bird
populations caused by other changes) is one of the things that the BBS is
specifically designed to measure.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Evidently that is correct and was why the question was raised. I would think
given the effort, time and resources expended by volunteers and paid staff
that there are much better and newer scientific ways that these can be better
utilized with more accurate results. As someone has already mentioned the
need to be right is urgent in order to be sure of which trends are true and
which are not. Rather than a shotgun cure we need micro surgery to stop the
bleeding. Great strides have been made in science, although it is stated that
at this time these counts are the best we have.
Routes near roads are specifically more suspect and far more likely to
sustain degradation than other areas and it is a very thin slice at that.
Point counts seem better suited but also probably need looking into for
better standards but that's another question.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
This topic continues to be debated among BBS folks. There are some
studies, however, that show that the overall trends in many species sampled
on, say, spot-map census plots, generally parallel BBS trends in the same
region.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
In this war against those that have only a regard for profits you need facts
not trends and samples. I have no reservations about the declines but I do
have reservations about giving the enemy fodder for his cannons such as the
Tanager affair. Again the time, effort and resources expended may be better
used in another format or do you ride a dying horse to the ground. Many have
much time invested and their views are understandable.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The BBS does adjust for changes in observers on established routes through a
process of weighting the observer's results. A new observer's results are
not weighted as heavily as an observer who has run the route several
consecutive years. This is because paired studies have shown that a new
observer on a route, even if he/she is a very competent birder and very
familiar with the technique, does not record as many birds as a competent
observer who has run the routes several times.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Another chink in the armor. Is there a competency test given participants?
How are they judged and who does the judging? How do you weight each
participants physical and mental abilities and then adjust for these
differences? If they can do that then with more habitat data they could
adjust those factors.
Hear is one of many statements I received from insiders:
"I have stood beside some of our surveyors, who couldn't hear a bellowing
croc if it was about to bite off their arm or identify a red-eyed vireo even
if it sat on their shoulder - by sight or sound. Still the data accumulates"
Still as a devils advocate, is the BBS survey a scared cow that those deeply
involved have too much time invested and jobs hanging on the line to just say
there is a better way? I am sure there are good points about the survey but
caution is a must when using such data especially when some you are trying to
convince are working against your every move when it comes to habitat.
OK, start shooting;o)
Good Birding!!!
Jeff R. Wilson
OL' COOT / TLBA
Bartlett Tenn.
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