THE BIRDS OF NORTHERN THAILAND 393 



POMATORHINUS SCHISTICEPS RIPPONI Harinston 



Shan Yellow-billed Scimitar Babbler 



Pomatorhinus ripponi Harington, Bull. Brit. Orn. Club, vol. 27, 1910, pp. 9-10 

 (Shan States; type specimens, in British Museum, from Pyaunggaung, North- 

 ern Shan States). 



Pomatorhinus olivaceus ripponi, Williamson, Journ. Nat. Hist. Soc. Siam, 1918, 

 p. 16 (Doi Nga Chang, Muang Wang).— Gyldenstolpe, Ibis, 1920, p. 488 (Doi 

 Nga Chang, Muang Wang). — de Schattensee, Proc. Acad. Nat. Sci. Phila- 

 delphia, 1929, p. 532 (Doi Suthep).— Deignan, Journ. Siam Soc. Nat. Hist. 

 Suppl., 1931, p. 136 (Doi Suthep). 



Pomatorhinus olivaceus olivaceus, de Schatjensee, Proc. Acad. Nat. Sci. Phila- 

 delphia, 1928, p. 567 (Doi Suthep). — Chasen and Boden Kloss, Journ. Siam 

 Soc. Nat. Hist. Suppl., 1932, p. 244 (Doi Suthep). 



Pomatorhinus schisticeps nuchalis, de Schatjensee, Proc. Acad. Nat. Sci. Phila- 

 delphia, 1934, p. 1S5 (Doi Suthep, Doi Chiang Dao).— Riley, U. S. Nat. Mus. 

 Bull. 172, 1938, p. 323 (Khun Tan, Doi Langka).— Greenway, Bull. Mus. 

 Comp. Zool., 1940, p. 169 (Doi Ang Ka, Doi Nang Kaeo). 



Pomatorhinus nuchalis, Deignan, Journ. Siam Soc. Nat. Hist. Suppl., 1936, p. 105 

 (Doi Suthep). 



The present form is rather common, wherever it finds a satisfactory 

 environment, throughout the districts west of, and including, the Khun 

 Tan range, occurring chiefly on the mountains between 3,300 and 

 5,500 feet but, in the neighborhood of Muang Fang, descending into 

 the lowland evergreen. 



Outside of the breeding season, the yellow-billed scimitar babbler 

 is found in noisy flocks of as many as a dozen individuals, which keep 

 to such cover as patches of lalang grass and fallen trees overgrown 

 with vines. The ordinary call is the soft double whistle of the genus 

 but it has also many harsh, chattering notes and I once took a solitary 

 bird from the top of a high tree, where it was uttering loud, melodious 

 whistles. Stomachs examined by me contained only insects. 



An example from Ban Muang Sum, December 24, and another from 

 Doi Suthep, January 23, had the gonads slightly enlarged, but still 

 others taken at that season had them inactive. Juveniles have been 

 collected on Doi Ang Ka, April 10 and 27, and on Doi Khun Tan, 

 October 20; the Khun Tan specimen is just beginning postjuvenal 

 molt. A long series of adults, taken at various localities between 

 July 11 and December 17, are in postnuptial molt. It appears that, al- 

 though the majority of birds breed during the spring months, odd 

 pairs do so in the cold weather and yet others in the rainy season. 



Adults had the irides pinkish yellow; the bill bright wax yellow, 

 with the narial membranes and the base of the culmen blackish ; the 

 feet and toes plumbeous, tinged violet or greenish; the soles yellow; 

 the claws horny white or yellowish horn. Juveniles differed in having 

 the irides creamy gray or tan and the claws horny brown. 



