Demiegretta Blyth, Jour. A. S. Beng.. xv, p. 372 (1846).
Type by mon., Demiegretta concolor = D. sacra Gmelin.
Demiegretta differs from Egretta in having the train composed of lanceolate feathers, shorter than the disintegrated plumes of that genus. The breast-plumes also are lanceolate and are worn all the year round and not in the breeding-season only; the nude portion of the tibia is less in extent.
In colour the Beef-Herons are dimorphic, being either all grey or all white, though intermediate piebald birds are common. The colour-phases are not yet understood. It does not seem to depend on sex or age, as many birds breed in all three phases of plumage, whilst in some cases a grey bird mates with a white, though generally the colours mate together. In one case certain young white birds moulted into grey plumage in the eighth month and there are specimens in the British Museum which seem to be in course of assuming a grey from a white plumage.
The genus is represented on the sea-coasts of Africa, Arabia, India, the islands of Southern Asia to Australia and the Pacific Islands. Two species are found in India.
Key to Species.
A. Crest of thick, rather hairy feathers; a white streak only on centre of throat in grey birds……………..B. sacra, p. 351.
B. Crest of two long feathers; whole chin and throat white in grey birds……………..B. asha, p. 353.