 The newly hatched American white ibis is covered with purple down feathers , deepening to dark brown or black on the head and wings . The chest is often bare and there can be a white tuft on the head . The irises are brown . The exposed skin is pinkish initially , apart from the tip of the bill which is dark gray , but turns gray within a few days of hatching . The bill is short and straight at birth and has an egg tooth which falls off between days five and nine , and develops three black rings from around day six , before turning gray by around six weeks of age . The gray to sandy gray brown juvenile plumage appears between weeks two and six , and face and bill become pink a few weeks later , while the legs remain gray . The irises have turned slate @-@ gray by this stage . Once fledged , the juvenile American white ibis has largely brown plumage and only the rump , underwing and underparts are white . The legs become light orange . As it matures , white feathers begin appearing on the back and it undergoes a gradual molt to obtain the white adult plumage . This is mostly complete by the end of the second year , although some brown feathers persist on the head and neck until the end of the third year . Juvenile birds take around two years to reach adult size and weight . 
