Trick for the winter: That's why you should have a tennis ball in the garden. The ball can prevent small parts of the water from freezing over.
Wild animals can then drink from this hole. It also provides oxygen for the living creatures in a pond. Even in the cold season you can attract birds that overwinter in Germany to your garden. Even self-made food is possible. Just be careful, if the ball is very light, like a table tennis ball for example, it can easily fly away.