[colonelboris]

Does anyone know if there are many species with marked differences in behaviour between their summer and winter grounds?

For all I know, nightingales could be tame as anything when wintering in Africa and only shy when they get here.

I know that some birds don't normally flock together in the summer, but do for winter forays (waxwings, etc), but I just wondered if there was anything more intersting than that.

[Bob Brent]

There are differences in most migrant birds, not only at the destination points, but also during migration. I can give you a couple of examples from Tobago. The Northern Waterthrush is highly teritorial in it's breeding grounds throughout Northern North America, yet at wintering grounds here the birds gather at dusk to bathe in small groups. Juvenile Osprey which are known to feed almost entirely on fish, spend thier first three years regularly hunting birds over mangrove and suburban area's. Also remember that the birds entire lifestyle changes during migration, where body mass is built up for the long nightly journeys that the birds take.