Tips for winter feeding

Feed birds only when it is necessary, not in the summer or during the breeding season.
It is not healthy for the natural growth of young birds if they get the wrong and/or monotone food. Feeding birds is only necessary during the winter if there is snow or frost, during which the food can't be reached. Always take care that the food is not placed in the snow, or put it in a manmade nest box.
If there is snow it is not necessary give them water. The birds pick the snow. In this way they get fluids inside. If there is no snow and the water is frozen, you can give them water in a small bowl. If you do this, cover it so that the birds can drink from it, but can't bath in it.
You can cover it with a flower pot or chicken wire.
You should refresh the water several times during the day. It is necessary to take care that the water does not freeze. You can do that by placing the bowl on a mat of 16 watts. (These can be bought with several specialized animal stores).
Do not put salt in the water. If you do that, the birds get more thirst and they get problems with their intestines.

Another tip for bird lovers that live near a park with ducks and geese:
To provide these animals with water, you can use an small empty bucket.

Pictures:
Top picture: An aviary of the bird shelter in winter.