White-shouldered ibis

Description

The adult of this large ibis stands 60–85 cm tall,with males being slightly larger and having slightly longer bills than females.Its only available biometrics are measurements from a single unsexed specimen originating from the 19th century,which include a wing length of 419mm,culmen length of 197mm,tarsus length of 83mm and tail length of 229mm.The plumage is brownish-black,with glossy blue-black wings and tail,and a bare slate-black head which has also been reported as blue or white.A conspicuous neck collar comprising a bluish-white band of bare skin which is broader at the back and narrower at the front extends from the chin around to the nape at the base of the skull.The pale blue is most easily detectable at close range,although this collar has been noted to be completely white in some individuals.The legs are dull red,the iris is orange-red,and the large de-curved bill is yellowish-grey.The white-shouldered ibis probably owes its name to the clear white observed on the upper part of the neck and chin in some individuals,which may appear as “white shoulders” in flight.In flight,it is also identified by its conspicuous white wing patch,which is visible only as a thin white line when the wings are closed.The white-shouldered ibis is morphologically similar to its Indian congener the black ibis Pseudibis papillosa,but lacks the red tubercles on the nape which are present in the latter;and is slightly larger,more robust and has a longer neck and legs.he tail also appears to be shorter and spreads downwards in contrast to straight in the black ibis.The juvenile has dull-brown plumage along with a tuft of brown feathers on the bluish-white nape,a grey-brown iris,pale yellow legs and dull white feet.