[TN-Bird] Loving some birds to death by banding

  
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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     Visit the Tennessee Ornithological Society
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    TN-Bird Net Owner: Wallace Coffey, Bristol, TN
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