250 BIRDS OF BRITISH BURMAH. 



Genus DEMIEGRETTA, Bl 



615. DEMIEGRETTA SACRA. 



THE BLUE REEF-HERON. 



Ardea sacra, Gm. Syst. Nat. i. p. 640 ; Hume, Nests and Eggs, p. 618. Ardea 

 jugularis, Forst., Wacjl. Syst. Av., Ardea, sp. 18. Demiegretta concolor, BL 

 J. A. S. B. xv. p. 372. Demiegretta sacra, Salvad. Ucc. Born. p. 346 ; Wald. 

 Ibis, 1873, p. 318 j Hume, S. F. i. p. 254, ii. p. 304 ; Hume $ Dav. S. F. vi. 

 p. 481 ; Hume, S. F. viii. p. 114. Herodias concolor, Bl. B. Burm. p. 160. 



Description. The adult in full breeding -plumage is everywhere of a deep 

 blackish slate-colour ; the feathers of the head almost black ; the feathers 

 of the upper breast greatly elongated, as are those of the middle back, 

 some of the latter disintegrated ; the elongated feathers of a paler slaty 

 grey, those of the breast not exceeding 3'5 inches in length, those of the 

 back reaching quite to the end of the middle tail-feathers. In most 

 specimens there is a somewhat brownish ashy tinge on the abdomen and 

 vent-feathers. In some adults there are not more than one or two white 

 feathers on the whole chin and throat ; in others there is a well-marked 

 pure white streak from the tip of the chin down the centre of the throat 

 fully four inches in length, and between these two extremes every inter- 

 mediate amount of white occurs. There is a broad full occipital crest 

 about an inch long. (Hume.) 



A certain proportion of these Herons are pure white throughout, with 

 dorsal and pectoral plumes developed as in the ashy birds above described, 

 except that the dorsal plumes are sometimes longer, exceeding the tail by 

 one inch. It seems to be generally recognized now that the white birds 

 and the ashy ones belong to the same species ; in fact the nestling birds 

 are sometimes white, sometimes ashy and occasionally pied ashy and white, 

 but the old birds apparently never exhibit this latter pied plumage. 



Length 21 to 24 inches, tail 3 to 4'25, wing 9*85 to 1T75, tarsus 2'7 to 

 3-1, bill at front 2'65 to 3'5. (Hume.) 



In nonbreeding -plumage the pectoral tuft and the dorsal train are 

 wanting. 



An allied species D. gularis differs in having the whole chin, throat and 

 sides of the head as high up as the gape and the ear-coverts white, and it 

 is also larger than D. sacra. 



The Blue Reef-Heron occurs along the whole coast of British Burmah. 



It is found in the Andaman and Nicobar Islands, and it is spread along 

 the shores of the whole of Eastern Asia, from Japan southwards to the 

 islands of the Archipelago, Australia, and some of the islands of the 

 Pacific Ocean. 



