The purple gallinule is a medium-sized rail, measuring 26–37 cm (10–15 in) in length, spanning 50–61 cm (20–24 in) across the wings and weighing 141–305 g (5.0–10.8 oz). Males, averaging 257 g (9.1 oz) in mass, are slightly larger than females, at 215 g (7.6 oz) on average. An adult purple gallinule has purple-blue plumage that will shine green and turquoise when in good lighting. Adults also have a pale blue shield on their forehead, which connects with the red and yellow bill. Darkness or low light can dim the bright purple-blue plumage of the adult to make them look dusky or brownish, although the forehead shield color differentiates them from similar species such as common gallinules. Immature purple gallinules are a brown-bronze color, with purple feathers on chest, and the bill and forehead shield is pale in color. Juvenile birds are light brown with hints of green-bronze on the wings and back, and white under-tail coverts.Taken from: Wikipedia