HA! Finally my school, Indiana State is famous for something besides Larry Bird!!
Thanks Cecil.
Indiana State - Where the men are men and the ducks are skittish. 
Duck #1 - Whatcha gonna do this afternoon?
Duck #2 - Dunno, I’ve got half a mind to take a nap.
The overwhelming majority of people have more than the average (mean) number of legs. – E. Grebenik
In your (Cecil’s) discussion, you mention that the ducks on the end keep their outer eye (the one facing away from the group) open 86% of the time, while the ducks in the middle keep it open only 56% (if i remember correctly) of the time. My question is, how can the ducks in the middle have an outer eye, given the part of the group is on either side of said duck??? I would appreciate a clarification, please…
I wonder if practical joker ducks will pretend to sleep on the outside, and then fly away when the middle ducks are snoozing, leaving them unprotected 30% more.
Gromit, there were four ducks in each row. Thus, the second and third ducks sat closer to the one end than to the other. I presume the “outer” eye would have been the one pointing towards the close end.
Holger
[[I wonder if practical joker ducks will pretend to sleep on the outside, and then fly away when the middle ducks are snoozing, leaving them unprotected 30% more.]]
I think the reason ducks “stay awake” on the outside and “sleep” on the inside (where the other ducks are) is to protect themselves; not the other ducks.
Jill
Holger, I see your point, but I’m not sure that birds can “count.” Seems like I remember seeing one of those nature shows in my youth, and they mentioned that birds can’t really tell one from two. Perhaps Cecil (or the author of the original study) should have been more specific…
Gromit, even if ducks can’t count, I’m sure they’ll have some feeling of quantity, either absolute (many/few) or relative (more/less/fewer). If that fails, they certainly have some idea of distance (towards the edge of the group), without which they’d be unable to fly, swim, or eat.
Interestingly, Cecil, didn’t tell us how much of the time ducks kept open their inner eyes. Maybe that one was at 53% as well. Or maybe it was 50%, and the difference is negligible; maybe it was caused by just one duck that could count and raised the average. 
Holger