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From: sandee@sun16.scri.fsu.edu (Daan Sandee)
Newsgroups: rec.aviation,rec.birds
Subject: Re: The most competent soaring pilots are...
Message-ID: <676@sun13.scri.fsu.edu>
Date: 13 Sep 90 19:47:45 GMT
References: <1990Sep11.125658@unify.com> <933@jli.UUCP>
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In article <933@jli.UUCP> andy@jli.UUCP (Andy Johnson-Laird) writes:
>Yeah! I was soaring just east of Mount Hood about two weeks ago 
>and hit strong thermal at about
>1500 agl. I shutdown the engine and retracted it (sorry purists, but it's
>a selflaunching sailplane) and went on about the business of gaining alttitude.

How I used to hate those things. But that was a long time ago, and I am sure
my attitude was of a horseman objecting against the first automobiles ...
still, I'm glad my soaring career was over before these damn things became
common.

>When I got to about 3,700 agl I suddenly noticed I was not alone.
>There was what we Brits call, a "bloody great bird" in the thermal with me.
>I would estimate a wing span of at least 6 feet (though it's difficult to 
>get scale at times like this). I remember noting the underside of the bird
>had lots of white dappling. I also noticed that this BGB (BG bird) was
>holding....wait for it.... a large *fish* in it's talons. 

A large all-dark bird with a dappled underwing surface is an immature bald
eagle. Six feet span would be about right. Great!
>
>It's talons were positioned "fore and aft" holding the fish with its head
>towards the front so as to minimize the drag. (Parasitic or Piscine Drag
>being important to avoid).
>  {..}
>Has anyone ever seen birds carrying their prey this high off the ground?

Good observation.
Ospreys routinely carry their prey aligned fore-and-aft, but I've never seen
a bald eagle do so.
Ospreys also may fly around with their catch for some time - I've always
thought to show off to their mate, and so forth (as part of the courting
ritual ospreys give each other nice juicy fish as a present, and they hand
it over in mid-air!). But an immature doesn't display or court, and it's a
bit early for the breeding season anyway.
>
>As a final thought, how do these marvelous birds find thermals? What
>do they use as a vario? I can't believe *they* look for sailplanes
>as a means of finding a thermal! :-)
>Andy
I've often wondered. In the mountains, they just sit somewhere until they
feel a thermal taking off. Also, I've often enough found lift just by the
seat of my pants, and I'm sure they can do the same (except they don't have
pants, but you see what I mean).

P.S. Much as I am delighted to be able to address two of my interests in 
one posting, I would urge that follow-uppers consider whether their
contributions are appropriate to BOTH newsgroups, and post accordingly.

Daan Sandee                                           sandee@sun16.scri.fsu.edu
Supercomputer Computations Research Institute
Florida State University, Tallahassee, FL 32306-4052  (904) 644-7045