Immature Robin

From the U.S. Fish and Wildlife Service:

"Who are you calling immature?" This immature robin displays plumage different than that of its parents that will help it camouflage. This time of year you may see a number of young birds exhibiting juvenile plumage. Be on the lookout, but please, leave them alone if you come across them. They're just trying to be more mature. smile emoticon

Photo: Sean Varner, FWS.GOV