Indian Spot-billed Duck

The Indian Spot-billed Duck is a large, mainly grey-brown dabbling duck with a scaly body pattern, pale head, dark cap and eye stripe. Its black bill ends in a conspicuous yellow tip and carries red spots at the base in adults. A green wing speculum bordered by white flashes in flight. Male and female plumages are similar, although their voices differ (Wikipedia, general species account).

This species uses freshwater lakes, marshes, rivers and flooded cultivation across South Asia, feeding by dabbling for aquatic vegetation, seeds and invertebrates. It is generally resident rather than strongly migratory and often occurs in pairs or small groups. The nest is placed in vegetation near water, and the female incubates the eggs. Japanese observations fall well beyond its core range and are treated as unusual occurrences (Wikipedia, general species account; Wildlife of Japan occurrence records).