what is the selective advantage for young gulls to have different
plumage patterns as they mature? is this a visual cue to adult
birds so they won't be so mean to the youngsters when they are
fighting over a tasty french fry? does this grey plumage make the
young birds less visible to predators? why is it that these birds
maintain this "immature" plumage for several years (depending upon
the species, of course)?

deborah wisti-peterson
nyneve at u.washington.edu