[TN-Bird] Fw: [ia-bird] Re: Hooded Crane (speculative)
- From: kbreault <kbreault@xxxxxxxxxxxxx>
- To: tn-bird@xxxxxxxxxxxxx
- Date: Thu, 9 Feb 2012 08:57:27 -0800 (PST)
Continuing speculation from other lists re our putative Hoodie given the IN
finding.
Kevin Breault
Brentwood, TN
----- Forwarded Message ----
From: "Dinsmore, Stephen J [NREM]" <cootjr@xxxxxxxxxxx>
To: IA-BIRD <ia-bird@xxxxxxxxxxxxxxxxxxx>
Sent: Thu, February 9, 2012 10:36:45 AM
Subject: [ia-bird] Re: Hooded Crane (speculative)
Chris et al.-
I think the main point here is that we advance our knowledge of birds
(distribution, patterns of vagrancy, etc.) by taking a conservative stance on
unlikely events. In the simplest terms, a hypothesis has been posed that a
Hooded Crane arrived in North America naturally, unassisted by humans.
Logically, the birding community should strive to amass evidence for, and
against, this hypothesis as a means of supporting or refuting it. Support in
favor of the hypothesis would have little merit if we didn't pursue it with a
healthy amount of doubt! Constructive skepticism is, in my opinion, an
essential
part of this debate, independent of the ultimate conclusion about its origin.
It
is also important to recall that the topic of origin in birds spans a continuum
of evidence: few of us would consider counting a Lilac-crowned Parrot in Iowa
as
a wild vagrant from Mexico (a pair frequented Ames many years ago), but almost
all of us count as wild any Eurasian Wigeon that appears in the Midwest. Why?
Because we have differing levels of evidence for each scenario, which helps us
reach conclusions about the most likely origin (wild, or something else).
I am not sure where the Hooded Crane falls, although I am by no means convinced
that the evidence unequivocally supports a wild origin. Chris makes a good
point
about its occurrence with Sandhill Cranes in Nebraska. But it is worth pointing
out that the cranes in Nebraska are (mostly) a different subspecies than those
in Tennessee and Indiana. If the bird originated in Asia and reached the Great
Plains with Lesser Sandhill Cranes, much as we surmise happens with Common
Cranes, then why did it make a beeline east and join Greater Sandhill Cranes?
Regardless of the birds ultimate acountability this represents a neat
opportunity to view a spectacular looking bird in the Great Plains!
Steve
**********
Stephen J. Dinsmore
Department of Natural Resource Ecology & Management Iowa State University
339 Science II
Ames, IA 50011
Phone: 515-294-1348
E-mail: cootjr@xxxxxxxxxxx
Web: http://www.public.iastate.edu/~cootjr/
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