132
156
G. A. C. HERKLOTS
district)." In 1928 a census of the herons and heronries in England and Wales was carried out and it was shewn that there are about 3,900 pairs of herons occupying 278 sites, an average of about 14 nests per heronry. There has just been completed a census of the great crested grebes, the number of pairs being computed at between 1155-1162 occupying 490 sites. But the bitterns are very much rarer than either of these other two birds and only a few pairs now breed each year in protected localities on some of the Norfolk Broads. A census of the Heronries of the New Territories and the Egrets and Herons that inhabit them would be quite a simple matter but it would be impossible to make any count of the number of Bitterns that frequent these territories because their nests are built close to the ground in reeds and grasses and are extremely difficult to find.
HONG KONG SPECIES :---According to Gee's "A Tentative List of Chinese Birds" 1926, five species of Bittern occur in China and all these are resident in, or visit, Kwangtung at some time of the year. These five species are Schrenck's Little Bittern, common in Kwangtung May to October; Chinese Little Bittern, very common in Kwangtung in the summer, breeding May to August, less common in the winter; Chestnut Bittern resident in Kwangtung, common April to October rare in winter; Yellow-necked Bittern, Kwang- tung May to October, only a few remaining during the winter; and the Eastern Great Bittern which is common in Kwangtung during the spring and autumn, rare in winter. Although, in all probability, all these species may be seen in our Territories yet our knowledge of the Bitterns is confined to scattered observations on three species only. Descriptions of all five are given below in the hope that observers may add to our knowledge of this interesting group of birds.
The three species known to occur in the Colony are:-
The Chinese Little Bittern, Ixobrychus sinensis sinensis, Gmelin. Our records of this species are confined to the months of September, October and March, which is curious as the species is probably very much commoner in the summer. This bird has a wide range being found throughout almost the whole of Asia from India to Manchuria and Japan in the north to the Malay Peninsula and the islands north of Australia in the south.
The Chestnut Bittern or Cinnamon Heron, Ixobrychus cinnamomeus, Gmelin. Caldwell writes that he finds that this bittern is not as common in south China as the other small bitterns and our single record of this species supports this. Similar in distribution to that of the Chinese Little Bittern.
The Eastern Great Bittern, Botaurus stellaris orientalis. The largest of the Chinese bitterns, distributed throughout eastern Asia. Our records of this species are confined to the months November, December and January though it is probably much commoner in spring and autumn.
This species is called the Common Bittern in the Philippines.
The two other species which probably occur in the Colony are:- Schrenck's Little Bittern, Ixobrychus eurhythmus, Swinhoe. Recorded from eastern Siberia to Japan in the north and Borneo and the Philippines in the South.
The Hong Kong Naturalist.
The Birds of Hong Kong-Part XI
157
The Yellow-necked Bittern or Black Bittern, Ixobrychus flavicollis flavicollis (Latham). Ranges from India to South China in the north to the Malay Archipelago and the Philippines in the south. From time to time we have received records of bitterns seen in the neighbourhood of the U.S.R.C, grounds in Kowloon. The birds seen may very likely have been this species, as Caldwell writes of it." This heron is distributed pretty generally throughout the plains and among the foot hills, but seems to prefer regions about the habitation of man."
DESCRIPTION AND FIELD IDENTIFICATION:-The Notes given below are derived from a selection of books of reference on the birds of China, the Philippines, Borneo and Singapore and from a skin of the Chinese Little Bittern. The most striking features are given in italics.
The Chinese Little Bittern. Length 13-14 inches, will 234 inches. MALE. Above carthy brown slightly tinged with rufous more especially on the scapulars, wing coverts clay brown, edge of wing white, primary coverts and quills black, inner secondaries brown tinged with rufous, lower back, rump and upper tail coverts ashy gray. Tail black. Crown and nape black. Sides of face, ear-coverts, and sides of neck vinous, becoming chest- nut on the long frill-like feathers of the sides of the neck; throat white mesial- ly streaked with yellowish buff. Abdomen yellowish buff, thighs more tawny rufous; Lower abdomen and under tail-coverts white or yellowish white, un- der wing coverts white, quills slaty below with paler grey at ends. On each side of upper breast a patch of dependent feathers of a blackish ground with yellowish buff margins. Facial skin green, upper mandible dark brown on the culmen and pinkish brown on the margins, lower mandible pinkish brown, greenish towards the tip. Toes pale yellow, tarsus flesh colour, FEMALE. More rufous above, feathers of back being rufous-brown with yellowish buff margins.
The Chestnut Bittern.
Length 15-16 inches NALE, Entire upper parts cinnamon-rufous including wings and tail, sides of face and car coverts. Under surface much lighter, tawny buff, throat ashy white with a median streak of tawny rufous, which extends down throat and fore neck being streaked with blackish longitudinal marks on the outer webs of the feathers. Lower throat, fore neck, breast, sides of body, and thighs tawny rufous; abdomen white, under tail coverts tawny buff. On sides of upper breast a patch of dependent feathers with black centres and axillars and under surface of quills pale chestnut.
tawny-buff, Facial skin reddish purple. Bill yellow except culmen which is dark brown.
Legs and FEMALE. toes greenish yellow.
Differs considerably from the male. Mantle and back uniform dark brown, wing coverts and scapulars dingy brown with sandy buff margins. Greater coverts, primary coverts and quills principally chestnut. Crown and nape dusky brown, tail feathers dull chestnut. Frilled feathers on sides of neck with brown centres and yellowish margins. Under surface yellowish buff thickly streaked with dark brown. Sides of throat whiter. Mesial streak distinctly rufous. Dependent plumes with black centres and yellowish buff margins. Thighs chestnut, under
tawny buff or rufous margins. Under wing coverts
December 1932.
133