** Michael P. wrote -


> Ray, probably the eatin's better in the grass than on the beach. If the
> adult CAGU are so severely stressed by the double whammy of long-distance
> migration *plus* molt as to suffer significant mortality, it might make
> sense that they'd appropriate the best feeding areas. Hm, but if that's so,
> and assuming parents and juvs leave at roughly the same time, then the juvs
> *should* beat them out to the coast because their plumage is complete and as
> fresh as it's going to be, and they'll be able to make better time. The
> adults in poor plumage would need to make more pitstops to gas up.

My theory is that it all comes down to food supply, also, but food supply on the
breeding grounds, not enroute. We all know one of the preferred foods of California
Gulls - grasshoppers. And the time of the prime 'hopper hatches in the boreal
latitudes of the species' range is end of July beginning of August depending on
weather conditions. The hatches usually run for about two weeks, enough for any bird
to tank up for the next leg. Those birds which find a good supply of grasshoppers
have a better chance of completing the migration over/through the mountains.

- Jack



Jack Bowling
Prince George, BC
jcbowling at mindlink.bc.ca