

Oeder AEDEIFOEMES.] 



[Family AKDEIDiE. 



DEMIEGRETTA SACRA. 



(EEEF HEEON.) 



m'y- 



Ardea sacra (G-melin), Buller, Birds of New Zealand, vol. ii., p. 129. 



On the beautiful cocoa-nut island of Wakaya, where I spent a week with Captain Langdale, B.N., 

 during my last cruise through the coral islands of the Western Pacific, I saw, and ultimately 

 secured, a snow-white example of this species, which is known to be dimorphic. It was paired 

 with a bird in the ordinary bluish slate-coloured plumage, which also in the end fell into 

 my hands.* 



Professor Moseley writes ('Challenger Naturalist,' p. 291): "A small Heron (Demiegretta 

 sacra) wades about on the coral reefs at Tonga, and catches small fish, and is also to be seen 

 frequently inland all over the island. This bird changes its plumage from pure white to uniform 

 grey, and all stages of parti-coloured plumage were to be seen during our visit. Contrary to the 

 usual rule, the bird is white when young, and dark in the mature stage. Hence the ancestors must 

 have been white, and the race is assuming a darker plumage for protection." 



Dr. Sharpe ('Catalogue of Birds,' vol. xxvi., p. 141) writes: "The white streak down the 

 throat is often absent or reduced to a few spots. It appears to be absent equally in quite 

 young birds as well as in old ones also, and it may be the result of inherent melanism in the 

 species. The white form is exactly similar in size to the grey form, and, when adult, has the 

 same ornamental plumes. In the Pacific Islands the two forms appear to inter-breed, and 

 produce white young ones mottled or streaked with slaty-grey. I have been unable to recognise 

 any of the many forms into which the Beef Heron has been subdivided by naturalists. Some 

 birds are larger, as may be seen by the measurements of the tarsi given in detail below, and these 

 larger birds have a slightly longer wing and a heavier bill, but no specific distinctions can be 

 founded on these variations, which are very slight." 



Mr. Pycroft writes : " I have obtained its eggs at the Black Bocks in the Bay of Islands. 

 The nest is loosely built, and is composed of twigs and rushes placed in some almost inaccessible 

 chasm." 



Young bird. — (September — first moult.) Plumage ashy-brown, changing to cinereous, the 

 new feathers showing up brightly against the old ; very narrow white streak on throat and only 

 about two inches in extent; no appearance of dorsal plumes. Bill dull brown, tinged with yellow; 

 legs and feet dull green, the soles yellowish ; bare space around the eyes yellowish-green ; irides 

 yellow. This bird was shot in a swamp by my son Percy, at Kaikoura, in the South Island. 



If Dr. Sharpe is right in bringing all these forms together under one head, the species has a 

 wide geographic range, including the coasts of Burma and the islands in the Bay of Bengal, the 

 Malay Peninsula and adjacent islands, on to Australia, New Zealand and the Pacific, and 

 extending north to the islands of the Bay of Corea. 







* " Mr. Gould mentions that some specimens of this Heron have the neck wholly white. One such bird is in the 

 Museum collection, and I think it probable that this may be the dimorphic form of the species." (Sharpe, 'Cat. Birds,. 

 Brit. Mus./ xxvi., p. 112.) 







