Black-headed Ibis
Threskiornis melanocephalus
The black-headed ibis is one of several large waterbird species in south and south-east Asia, with adults measuring 65–76 cm in length. The white plumage is starkly contrasted against a conspicuous naked black neck and head, and black down-curved beak. Tails of adults bear light grey ornamental feathers that turn jet black during the breeding season. During the breeding season, bare patches under the wing turn blood-red. The head of some breeding adults gain a blueish tinge, or very rarely have a pink or bright red patch behind the neck.
ID text from Wikipedia, CC BY-SA 4.0
Straw-necked Ibis
Threskiornis spinicollis
Straw-necked ibises are large birds, around 59–76 cm (23–30 in) long, with a bare black head and a long, downcurved black bill. They have a distinctive, highly iridescent plumage, which can appear fairly uniform dirty dark brown in indifferent light; the wings are dark, with an iridescent, multicoloured sheen in sunlight. They have a shiny blue-black back, with a metallic purple, green and bronze glow, and a dark collar. The upper neck is white, as are the underparts and the undertail; their legs are usually red near the top and dark grey toward the feet.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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