From: drintoul@matt.ksu.ksu.edu (David A Rintoul)
Newsgroups: rec.birds
Subject: BBQ for January 1993
Date: 5 Jan 1993 22:20:17 -0600
Organization: Kansas State University
NNTP-Posting-Host: matt.ksu.ksu.edu

The following is a regular monthly feature of the _Prairie
Falcon_, the newsletter of the Northern Flint Hills Audubon
Society in Manhattan KS.  This column will appear in the Jan.
1993 newsletter.  Hope you enjoy it.
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Birding questions asked anonymously will be answered by the anonymous
answer person.  Send your burning questions c/o the Prairie Falcon
editor, Dave Rintoul, Ackert Hall, Biology Division, KSU, Manhattan KS
66506-4901; or call him at 537-0781 (home), 532-5832 (work), or send
them by e-mail to drintoul@matt.ksu.edu.  All questions are
appreciated (even though you might not appreciate the answers), so
keep those cards and letters coming in!

1.  What do creepers find to eat on tree trunks in the winter? I have
a creeper that visits my yard several times a week, and goes over the
same branches again and again.  It always seems to find something, but
what could it be?  Surely it gets all the bugs the first time; isn't
it just wasting its time after that?

   It seems to me you answered your own questions.  As you commented,
"it always seems to find something," so it must not have gotten "all
the bugs the first time" nor can it be a waste of time.  In fact, that
the creeper returns indicates that the creeper is being rewarded for
both its time and effort.  There is experimental evidence that
demonstrates that if it would find food scarce it would not return
again to that site.  Of course, how do you know it's the same creeper?
Mostly what the creeper is finding is not necessarily "bugs" but bug
eggs (nits) and wee creatures hibernating in the crevices of the bark,
like spiders. But I have an exercise for you!  Let's assume that it is
the same creeper.  You say it goes over the same branches, but does it
follow the same route over these same branches?  I suggest that as you
watch the creeper forage try to remember exactly where it went (making
a gridded scaled map of the branch would help), and then go out and
mark its route with string (or something).  Then the next time it
comes back, see if it indeed follows the same route.  You might also
try to ascertain when it gets "something," and then tabulate the
frequency of "hits".  If you discover that it goes over the same
route, what is the success rate on subsequent visits?  Is there a
lower threshold of success after which it will not return to the same
route?  After you have completed your study, call up E. Dale Kennedy
(of Denison Avenue starling box fame) in the Division of Biology.
She's an avian behavioral ecologist, and I am confident that she would
help you with your analysis.  I've seen master's degrees awarded for
less interesting studies than the one I am proposing for you!

2. How do flocks of birds stay together, all turning the same way at
exactly the same time?  Every evening I watch a starling flock that
roosts in the trees behind my house, and it is amazing that they
always seem to stay together, twisting and turning in mid-air, without
losing anybody.  How do they do that?

    You are not alone in wondering about this phenomenon.  Is there
some extra-sensory communication among the individuals that conveys
the "quarterback's" signals so that they all turn the same way at the
same time?  Well, there is no evidence for that hypothesis.  Nor is
there evidence for a "quarterback." Who does decide?  Don't know.
What is known is that it is visual.  It is not EXACTLY at the same
time, but as the "lead" turns, adjacent individuals turn almost
instantaneously; then they all turn.  Schools of fish do it too.

-- 
Dave Rintoul                Internet: drintoul@matt.ksu.edu
Biology Division - KSU     Latitude 39.18, Longitude -96.34
Manhattan KS 66506-4901                         TCN: id2418
(913)-532-5832 or 6663                  FAX: (913)-532-6653