Flying south for the winter

It's that time of year again; the migratory birds form up and head south. Yesterday I snapped this gaggle of geese over Jeziorki; they headed north for a while towards town, then wheeled round to the west, then headed off south. By the time we see them again, we will have experienced another Polish winter.

I snapped a larger gaggle flying into Poland on 12 March this year. When will they return next year?

This time last year:
Gosh! It's 12 months since the parliamentary elections!
Hidden glories of London's Underground
London from the air