You need to provide shelter from the elements.
They need fresh water, and in the winter you might have to get it for them more often than you are used to.
One other thing I give is scratch grains which are high fat, and good to give in the late afternoon to help keep them warmer at the night.
I leave my birds outside during the winter and let them freeload. I could move them into the basement, but I don't want to smell them.