Often, people keep their bird feeders out in the winter and continue to feed the flying friends that visit their yard. I have always wondered what this did to the birds if this affected whether they traveled or not. The one question I really wondered, however, was what this did to birds who did stay in the area for the winter. After some research, I quickly found out that whether or not a bird will travel depends heavily on the weather and the species of bird that is in question. The birds that stay all winter, however, are the ones that I tried to focus on.
Every day there are woodpeckers and morning doves outside of my house eating at the feeders that are placed on a tree. While feeding birds in the spring and summer doesn't seem to be a problem because there is food naturally all over for a bird to eat, in the winter they almost depend on what they find from people's houses. An article by a nature blog that can be found here really helped me understand the impact of this.
While birds are naturally resourceful and can find seeds even in winter, when they come to a feeder and find that it is empty this can cause problems. Imagine a domesticated cat getting lost in the woods. The cat is used to being fed by its owner and is now on its own. It has natural instincts, but they have been muted by the attempted compassion and care from humans. These birds that are used to being fed from feeders could suffer due to their new habits, and it is important for this reason to keep feeders full during the hardest parts of winter.
While birds are nice to watch from your home or house porch, remember that in the winter they are an animal, and are trying to survive. The bird seed that is set out for them is survival, not just something they go to when they want a quick snack. If you are worried about them, and article found here suggests tapering off slowly and the birds will slowly stop coming to you, at least until it is warm again.
The positives to feeding birds through the winter is that their energy levels are elevated and they produce offspring that will be healthier. They are also quite fun to watch peck at suet in the garden. While birds that attend feeders are wild, just remember that their survival is questionable in the winter if they cannot find the resources they need, so it is important to keep their supplies filled, or wain them off to help them find other ways to get the nutrients they need in the harsh winter months, especially since this winter just started becoming so harsh.