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From: wander@csa2.lbl.gov (ADRIAN WANDER)
Newsgroups: rec.birds
Subject: Re: Atitlan Grebe (was:trivia quiz answers)
Message-ID: <6962@dog.ee.lbl.gov>
Date: 14 Sep 90 19:48:39 GMT
References: <1197@cluster.cs.su.oz.au> <675@sun13.scri.fsu.edu> <687@sun13.scri.fsu.edu> <49409@olivea.atc.olivetti.com> <689@sun13.scri.fsu.edu>
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In article <689@sun13.scri.fsu.edu>, sandee@sun16.scri.fsu.edu (Daan Sandee) writes...
>In article <49409@olivea.atc.olivetti.com> mjm@oliven.olivetti.com (Michael Mammoser) writes:
>>In article <687@sun13.scri.fsu.edu>, sandee@sun16.scri.fsu.edu (Daan Sandee) writes:
>> > LaBastille specifically notes that previous reports have surmised that it
>> > could fly, but refutes this based on
>> >  (a) direct observation, including reports from local inhabitants
>> >  (b) thorough examination of physiology (wing size and pectoral muscles).
>> 
>>	I read that it was a "weak flyer", though this was a general
>>literary reference and not a specific study paper. However, I was
>>wondering how one goes about verifying flightlessness through direct
>>observation. This would seem to be quite tricky. For instance, I have
>>directly observed thousands of Pied Billed Grebes, but can't recall 
>>ever seeing one fly. What conclusions can I draw from this? :-)
>> 
>>Mike
> 
>You're absolutely right. Direct observation can only provide negative evidence
>of flightlessness, which is inconclusive. Hence LaBastille spends several pages
>in her monograph on the bird's physiology with respect to its flying potential,
>and concludes that it most probably could not fly.
>As for Pied-billed Grebe : I can't remember ever having seen one fly, either.
>Though people who have seriously studied the bird no doubt have.
>There is circumstantial evidence of its flying capacity : it's a partially
>migratory bird, and even if there are no banding records, its seasonal 
>appearances and disappearances suggest migration ; unless you assume, as 
>scientists in centuries past did, that it hibernates in the mud, or gets
>turned into a barnacle, or something. And I do suppose it migrates by air -
>it doesn't walk, or swim the rivers, or something.
>(I'm not being sarcastic. Just making a thorough scientific investigation.:-))
> 
>Daan Sandee                                           sandee@sun16.scri.fsu.edu
>Supercomputer Computations Research Institute
>Florida State University, Tallahassee, FL 32306-4052  (904) 644-7045