>Does watching a movie from a theater seat fall within the accepted range of
>ferrets vision?
 
Seeing movement and seeing details of objects are processed separately in
the brain.  Because of this (in part), the ability to see movement can be
very different from the ability to see details of objects.  That is, its not
uncommon for an animal to be unable to see you when you're far away (they
can't make out the details enough to separate you from the background), but
to suddenly be able to see you as soon as you move.  Its not that ferret's
vision is bad in every respect, but that they're fairly nearsighted - they
can't make out details of objects at much of any distance.  But seeing
movement is a very different skill, and isn't as poor as seeing details.
Ecologically, seeing when there are other animals moving around is a pretty
important thing for any creature, whether predator or prey, and so we are
"specialized" to see and react to movement.  You've probably noticed this
yourself at times - you see a flash of movement out of the corner of your
eye, and you turn to look at it, but you can't figure out what it was that
moved.  Why don't you already know what you saw?  After all, you *did* see
it, or you'd never have turned to look at it.  It's not that the object was
moving too quickly for you to see, but rather that you only "saw" the motion -
your peripheral vision isn't that good at seeing details, so you weren't
able to identify the object, even though you saw that it was moving.  As
another example, have you ever seen someone at a distance, and not been able
to make out the face, but recognized her as soon as you saw her move?  They
were still too far away for you to make out details of who she was when she
was standing still, but you could still make out the movement.  These are at
least *similar* to what your ferret is experiencing - he's able to see the
motion at that distance, but if the birds weren't moving, he might never
know they were there (except perhaps by smell).  And even though they were
moving, he probably wouldn't have been able to tell they were gulls, rather
than some other bird with similar movement (even if he knew what gulls were).
[Posted in FML issue 1871]