Living Bird Magazine
Juvenal plumage: Light grayish brown head and body, back, tail, and wings. Flight feathers on wing same color as back. Bill black. Legs dark gray with pink overtones. Eyes dark brown to black.
First Winter (Basic I): Like juvenal, but head, throat, and breast lighter and more streaked. Bill black. Eyes dark brown.
First Summer (Alternate I): Head, neck, and especially the throat whiter, but still streaked. Wing feathers worn and paler. Mix of clean gray and mottled feathers on back. Bill black. Eyes dark brown.
Second Winter (Basic II): Head whiter, but neck heavily streaked. Back mottled brownish and light gray. Underparts white. Wing tips light gray, like back. Tail gray. Bill pale flesh at base, then black. Eyes dark brown. Legs dirty pink.
Second Summer (Alternate II): Head and neck largely white with conspicuous streaking. Back may be entirely light gray with a few brownish feathers. Underparts mostly white. Bill yellowish at base, then black with white tip. Eyes dark brown.
Third Winter (Basic III): Some dirty brown on otherwise white neck and head. Back light gray with only a few dull brownish feathers. Underparts white. Tail largely white with some dark smudging. Outer wing feathers (primaries) darker gray with white tips. Inner wing feathers (secondaries) light gray with broad white tips. Bill yellowish at base, then black with white tip. Eyes brown. Legs dirty pink.
Third Summer (Alternate III): Head and neck pure white or with only little streaking. Back all gray. Underparts white. Tail white with some dark smudging. Bill yellow with some red on lower mandible. Eyes brown.