What're they doing the rest of the year? I thought that was just like their homes or something. You've just shattered a very insignificant part of my reality but I can't cope lol
Pretty much anywhere! They like sheltered places like under shrubs and in brush, but they'll also sleep on the open ground or the water, like you've probably seen ducks and geese doing.
At the risk of spelling out common knowledge (it is common where I live), there's also lots of so-called migratory birds. During winter months, they'll fly into warmer regions near the equator and fly back for spring.
In particular, they may just not be able to find food when there's a thick snow cover.
Sorry to ruin your comment, even though I mean it, but they are only talking about the birds in the nests, not most birds that go with the flow like sheep.