The downy woodpecker is the smallest woodpecker that is native to north America. They are found through out most of the United States, except for the arid regions of the southwest, and the southern half of Canada and Alaska.They look similar to the larger hairy woodpecker which is also common with in most of the same range. When comparing the two species side by side the hairy is noticeably larger. However when trying to identify a lone bird look for black spots on the white tail feathers. If there are black spots then it is a downy, it is easier to see an example of this on the lower picture. If you can not see the tail then look at the beak. If the beak is shorter then the width of the birds head then it is a downy. If the beak is about the same side as the head then the bird is probably a hairy.
Like most woodpeckers the downy woodpecker does not migrate during the winter. Most insect eating birds must migrate for the winter to an area where they can still find insects to eat. Woodpeckers use their specially designed beak to forage inside of trees where they can still find insects and insect larva during the winter. Because of their small size downy woodpeckers often are able to forage where larger woodpeckers can not, like thin branches and weed stems. Males usually take these prize locations first. It is easy to tell the difference between males and females because males have a red band at the back of their head, see top photo, where the females do not, see bottom pic.