Green ibis

The green ibis (Mesembrinibis cayennensis), also known as the Cayenne ibis, is a wading bird in the ibis family Threskiornithidae. It is the only member of the genus Mesembrinibis.

This is a resident breeder from Honduras through Nicaragua, Costa Rica and western Panama, and South America to northern Argentina. It undertakes some local seasonal movements in the dry season.

The green ibis is a medium-sized ibis, with short legs and a long, slender, decurved bill. It measures 45–60 cm (18–24 in) in length and ranges from 700 to 890 g (1.5 to 2.0 lb) in mass. The sexes, which are identical in plumage, overlap somewhat in measurements, though the largest birds are male. Breeding adults have glossy greenish-black bodies, pale green legs and bill, and grey bare facial skin patches. Juveniles are much duller, but can be distinguished from the similar glossy ibis by their bulkier shape, shorter legs and broader wings. This species, like other ibises, flies with neck outstretched. Its flight is heavy, with fewer glides and jerkier wingbeats than its relatives.

It has a hollow, hooting, accelerating call, most often heard at dawn and dusk. Transcribed as kro kro or koro koro, the call is described as "mellow".

If seen in good light, the green ibis is distinctively dark, and unlikely to be confused with any other ibis. In poor light, however, it might be confused with the glossy ibis; the latter (which is bronzy-maroon in color) has longer legs and a slimmer build.