One of the most important things that birds need, even in the winter, is drinking water and a bath to keep their feathers in good condition and in place so they keep the bird warm.
Bird baths and puddles of weather that birds commonly use for this will freeze in cold weather and may remain frozen for days.
The pond was frozen over as well, but the pond creatures are all hibernating in the bottom of the pond and even the fish become dormant (like a type of sleep) when the pond is frozen. The ice was so thick I could walk on it.
Bye for now