Immature Description

Juvenal plumage: Dark brown head and body, face and nape paler. Back brown with light edgings to feathers. Throat, breast, belly, and undertail barred gray-brown and white. Tail black, edged in white. Flight feathers on wing blackish. Inner primaries and secondaries gray-black. Greater wing coverts black. Bill black, base getting lighter over time. Legs brown to black. Eyes dark brown.
First Winter (Basic I): Like juvenal, but head, throat, and breast whiter, and back is dusky gray with spots of brown. Belly is mainly white. Bill black with base becoming paler. Eyes dark brown.
First Summer (Alternate I): Head, neck, throat, breast, and belly mostly white. Dusky mottling still on belly, sides of throat, lower nape, and around eyes. Back blue-gray with varying amounts of spotting. Wing feathers worn and paler brown. Rump white. Undertail a mix of white and barred feathers. Bill pale with black tip. Eyes dark brown.
Second Winter (Basic II) : Head, throat, and belly mostly white. Dusky mottling on sides, sides of neck, and nape. Wing tips black, but outermost two feathers may have white spots. Back gray, wings mottled gray and brown. Rump and undertail white. Tail white at base with black outer half and white tip. Bill creamy white, with black band near white tip. Eyes dark brown. Legs bluish gray.
Second Summer (Alternate II): Head and neck largely white, but most birds have some dusky markings on lower nape. Wing tips black, but outermost two may have white spots. Back gray, wings mottled gray and brown. Underparts mostly white, with some birds having dark feathers in center of belly. Bill cream to greenish to yellow, with black band and beginning of red spot on lower mandible. Eyes dark brown. Legs and feet variable, cream to gray to greenish to yellow.
Third Winter (Basic III): Extensive grayish brown streaking on back of otherwise white head and neck. Back gray. Underparts white. Tail largely white with variable dark markings, usually toward the tip. Outer wing feathers (primaries) black with white subterminal spots on some. Bill yellow with black band and variable red spot. Eyes dark brown.
Third Summer (Alternate III): Head and neck pure white or with some dusky markings. Back all gray. Underparts white. Tail white with some dark smudging. Bill yellow with black band and some red on lower mandible. Eyes dark brown. Legs light greenish.