34 BULLETIN 17 2, UNITED STATES NATIONAL MUSEUM 



It breeds from southeastern Siberia to Cliina, the Japanese Islands, 

 and Annam; in winter it migrates southward to Borneo, Celebes, the 

 Malay Peninsula, and the Philippines. 



The three small bitterns occurring in wSiam may be distinguished in 

 any plumage by the following key: 



1. Tibia feathered to the heel Ixobrychus sinensis 



Tibia not feathered to the heel (lower part naked) 2 



2. Primaries grayish or slaty Nannocnus eury thmus 



Primaries liazel or rufous Nannocnus cinnamomeus 



DUPETOR FLAVICOLLIS FLAVICOLLIS (Latham) 



Ardca flavicollis Latham, Index ornithologicus, vol. 2, p. 701, 1790 (South China). 



One male and three females, Bangkok, June 26, 1924, June 1, 

 March 11, and October 28, 1926; two females. Bung Borapet, June 21, 

 1932. 



Dr. W. L. Abbott took a female in Trang but neglected to date it. 



The male from Bangkok taken October 28 (U.S.N.M. no. 308013) 

 is molting on the back, and the dark slate feathers of the wings and 

 back are being replaced by greenish-black feathers: the feathers of 

 the chest and abdomen are blackish, those of the abdomen having a 

 few buffy fringes; the feathers of the lower neck are slaty black, mar- 

 gined outwardly with white, the chestnut spotting of the foreneck not 

 extending to the lower neck; top of head and cheeks slaty black; sides 

 of neck ochraceous-buff . 



The three females from Bangkok differ from the male as follows: 

 Top of head and upperparts have a brownish cast; the abdomen is 

 drab; the cheeks are bay, and the bay spotting on the foreneck is 

 much more extensive and extends down onto the chest. These dif- 

 ferences seem to hold and are sexual, as Stuart Baker *° has stated. 



There is a male in the United States National Museum (no. 279414) 

 from Yachow, Ilunan, China, taken May 17, that is quite different 

 from, any description that I have consulted. It is a blue-green slate 

 above, on the hindneck, pileum, wings, and lower parts; the cheeks 

 darker; the bay spots down the foreneck sparse and not extending to 

 the lower neck; the white spotting on the median line of the neck also 

 restricted; otherwise as in the normal plumage. Tliis I imagine is 

 the full breeding plumage only assumed in old birds. 



Deignan ®' reports this form not uncommon south of Chiengmai 

 from July to September; August Aliiller **- records it from Junkseylon 

 (Puket); Robinson and Kloss,^^ writing of Southwest and Peninsular 

 Siam, say that it is rare wherever it occurs and that Williamson has 

 found it breeding at Bangkok. Owing to its nocturnal habits, the 



»o The fauna of British India, Birds, ed. 2, vol. 6, p. 368, 1929. 

 «> Journ. Siam Soc. Nat. Hist. Suppl., vol. 8, p. 173, 1931. 

 M Die Ornis dor Insel Salanga, p. 84, 1882. 

 •« Journ. Nat. Hist. Soc. Siam, vol. 5, p. 81, 1921. 



