[TN-Bird] Loving some birds to death by banding
- From: "michael sylva" <mtnsylva@xxxxxxx>
- To: "TN-bird" <TN-bird@xxxxxxxxxxxxx>
- Date: Sun, 22 Dec 2002 11:18:26 -0500
Since only a small sample of birds are captured and banded, I wouldn't expect
more than a small sample of banded birds to be recaptured ("recovered").
Thornton would have us believe that as many as 93% of banded birds are killed
as a result of banding - that's bad logic. The 7% recovery rate seems higher
than I would expect. Maybe someone else has calculated a hypothetical recovery
rate based on empirical data and sound mathematics. Also, I would think that
there are figures on the number of birds killed or injured during the banding
process. That would offer a fairer indication than a single anecdote, namely,
the calliope hummingbird.
It seems to me that Thornton is trying to arrange the facts to fit his
preconceived conclusion.
Michael Sylva
Del Rio TN
----- Original Message -----
From: William T. Thornton
Sent: Saturday, December 21, 2002 8:55 AM
To: tn-bird@xxxxxxxxxxxxx
Subject: [TN-Bird] Loving some birds to death by banding
Currently more than 6,000 folks have permits to band North American birds. Do
we really need that many?
Currently, of the birds banded each year, there is only about a 7 per cent
recovery rate. What happens to the other 93 per cent? What percentage of
birds trapped and banded end up dead as a result of the banding/trapping
experience? How many birds are killed in the trapping process before they can
be banded?
Historically, of the millions and millions of bird trapped and banded, there
has been only about a 6 per cent recovery rate. While it can be assumed that
we did learn a tremendous amount from this 6 per cent return rate especially in
the early years of banding, the absent 94 per cent may be telling us even more.
I do not have species specific data -- I am sure that for some species the
return rate on bands is more and on others less than this averaged data would
suggest. For instance, some time ago on TN-Birds it was posted that the return
on hummingbird bands was about 2 per cent -- if this is indeed valid data,
perhaps we should question the practice of banding every hummer we see in the
late fall/early winter. If some of the "rare" forms of western hummers are
trying to establish a foothold east of the Mississippi, they might have a
better chance without a leg band. Recently it was posted on BirdKY that a
Calliope Hummingbird in Ohio died in the banding process.
Nowadays, do we really need to continue to have more and more birds banded?
Are we running the risk of "loving some bird species to death?"
(The current and historical numbers above were calculated from data available
at http://www.pwrc.usgs.gov/bbl/homepage/100years.htm)
Terry Thornton
Rinnie, TN (North of Crossville on the Cumberland Plateau)
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