The white stork has a stout body, distinctive long neck and slender legs for wading. The iridescent black wing feathers contrast with the bright white plumage of the head, neck and body, and a patch of black skin surrounds the eyes. The bare legs and straight, conical bill possess a strong red color that is acquired as the bird reaches adulthood. The feathers of the lower neck and upper breast are elongated, forming a ruff that can be extended during courtship displays. The two sexes appear almost identical although males can be slightly larger. The plumage of juveniles is a dull, light brown color and has a downy appearance; the black bill and pale brown legs slowly acquire the adult coloration as the bird ages. The white stork is almost voiceless and largely silent, although it does communicate with brief hissing noises and, most importantly, bill-clattering; this is most pronounced during breeding and nesting and the sound can carry great distances. Juveniles are capable of their own rendition, often accompanied by extensive whistling and croaking.