Birds need water to drink and to groom themselves even in winter. As long as it's not freezing outside, the birds will always find a little spot. But if the temperatures drop below zero degrees, then it will be difficult for them too. Now we humans are in demand. If you have already set up a feeding place, you should add a small bird bath. You can easily make them yourself from a large leaf (e.g. rhubarb) and some concrete
I found a great video tutorial at Glitzer Else. Not only does she show us how to make such a potion yourself, she also gives a brief introduction to cement right at the beginning. A great help especially for newcomers in this field, because there are certainly enough of them on the market.
Important Notes
If you set up a bird bath in winter, you should make sure that the water does not freeze. The water must also be changed regularly, as diseases can be spread more easily by faeces, for example.
Do not put too much water in the drinker - a maximum of two centimeters high. If you want to be on the safe side, you can put a large stone in the bowl to create a safe place for the birds if the plumage is too wet.