During the winter, birds are often searching for food. There is a lot of birds that simply freeze to death, even in some what warmer weather. Do not stop feeding your birds, as they really are relying on you!
One way, you can always be sure to keep them fed is with an old trick, of buying a large container of peanut butter, and layering it on the tree bark near the feeders.
The squirrels often will eat much of it if you have them, but a peanut butter treat, every other day, can save them from starvation. It is full of protein that they need to stay warm, and will provide them with the nourishment they need.
In the end stages of winter, the situation is more dire than at any time of year. It is for this reason, you should cut up oranges, apples, bread, and any other left overs that you can find, for the squirrels and the birds. Do what you can to keep them alive, and be sure to keep a heated bird bath filled with water, as the warmer water really helps the birds stay warmer.
They do not have much to ask, only that you keep them in your schedule. We birders are such kind people! Thank you for doing your own part to save the birds this winter.