I have noticed--personally, and far more often by reports going back
over a hundred years--that here in the landlocked central counties
immature smaller gulls, however rare, (such as Sabine's, Bonaparte's,
little, and Franklin's gulls) are much more likely to show up here than
adults of these species, by and large in the fall season, when they are
inexperienced.
        My guess is that these first-year smaller gulls may often rely on blind
direction--that is, heading south where conditions are warmer--even if
they must fly over forests and mountains. Larger adult gulls are less
likely to migrate south overland (though some may spend the winter
foraging at large  unfrozen inland reservoirs, where young birds less
often stay for long), but most of them head east along the Great Lakes
and rivers to reach the sea via shortcut, as will small gulls once they
mature. This phenomenon seems to apply to jaegers, too; nearly all of
the jaegers seen inland in Ohio have been juveniles, with the mature
birds presumably taking the Seaway east.
        One way of looking at it is that many amateurs may head south overland
here, but the pros usually take the water route east. How do they learn
to adjust their migrations? One explanation might be that migrant flocks
of adult gulls may easily accept other adults as companions, but tend to
shun small youngsters...
        If anyone knows of research done on this phenomenon I'd be glad to have
a reference, or if anyone has speculations that would be good to hear as
well.
Bill Whan
Columbus

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