This cardinal looks like it's wearing a parka with the hood pulled back. Nope. It's likely victim of feather mites or lice. It could be abnormal molt, but this isn't a correct time of year for molt. Feather parasites on other parts of the bird's body could be preened away. The head poses an obvious problem. New feathers should grow within a few weeks. Courtship is underway right now. This bird probably won't make a good impression.