Many species undergo an additional partial molt each year, involving just some head and body feathers. This most often occurs in the late winter or early spring and is called the pre-alternate molt, resulting in the alternate plumage. Many species, but not all, have an alternate plumage. Because this is only a partial molt (not involving all feathers), the new feathers of the alternate plumage are worn alongside the older feathers of the basic plumage.