Newsgroups: sci.bio
Path: utzoo!rising
From: rising@utzoo.uucp (Jim Rising)
Subject: Behaviour
Message-ID: <1988Apr11.150532.15871@utzoo.uucp>
Organization: U of Toronto Zoology
Date: Mon, 11 Apr 88 15:05:32 GMT

I told myself that I wouldn't get into this hardwired vs. learned
controversy because I know nothing aboutanimal behaviour, but it 
does seem to me that some pretty complex behaviours must be 
essentially hardwired.

E.g., migration (in birds).  In order to migrate and home birds must
be able to assess any (or all) of several environmental cues, including
the position of the sun, stars, magnetic fields, and in some cases 
olfactory cues.  

The olfactory cues, as well as local landmarks, are likely learned.
However, how does a young bird "know" to where it must migrate in the
first winter, and how to find those places?  One could suggest that
they simply follow older birds--perhaps commonly their parents--in
order to get there, but there are many species (I suspect most) in 
which the young and adults migrate at different times.  So, e.g.,
a Red Knot that hatches on Ellesmere Island must be born with the
inclination to fly south in response to certain environmental cues,
migrate to southern South America, be able to find its way there, and
know when to stop--then do it the other way around in the spring.  It
can't learn the fall journey from its parents because they will have
been gone for a month when the young knots are ready to leave.

--Jim Rising
-- 
Name:   Jim Rising
Mail:   Dept. Zoology, Univ. Toronto
        Toronto, Ontario, Canada    M5S 1A1
UUCP:   {allegra,ihnp4,linus,decvax}!utzoo!rising