THE BIRDS OF NORTHERN THAILAND 349 



of the throat washed with rufous; the flanks grayish white, strongly 

 washed with yellow ; the remaining underparts light yellow. 



pteruthius erythropterus aeralatus biyth 



Tenasserimese White-browed Shrike Babbler 



Pteruthius aeralatus "Tickell" Blyth, Journ. Asiat. Soc. Bengal, vol. 24, 1855, 

 p. 267 ("Mountainous interior of Tenasserim" ; type specimen from Mount 

 Muleyit, fide Hume, Stray Feathers, vol. 6, 1878, p. 368). 



Pterythias aeralatus, Gyldenstolpe, Kungl. Svenska Vet.-Akad. Handl., 1916, 

 p. 63 (Khun Tan). 



Pteruthius aeralatus aeralatus, Williamson, Journ. Nat. Hist. Soc. Siam, 1918, 

 p. IS (Muang Wang, Doi Nga Chang). — Gyldknstolpe, Ibis, 1920, p. 479 

 (Muang Wang, Doi Nga Chang).— Riley, U. S. Nat. Mus. Bull. 172, 1938, p. 

 362 (Doi Ang Ka, Khun Tan, Doi Langka, Doi Hua Mot, Doi Mana, "Doi 

 Kiew Koh Ma"). 



Pterythius fiaviscapis aeralatus, de Schauensee, Proc. Acad. Nat. Sci. Philadel- 

 phia, 1928, p. 565 (Doi Suthep). 



Pteruthius flavisenprs aeralatus, de Schauensee, Proc. Acad. Nat. Sci. Philadel- 

 phia, 1929, p. 535 (Doi Suthep) ; 1934, p. 197 (Doi Suthep, Doi Chiang 

 Dao, Ridge just south of Doi Chiang Dao). — Deignan, Journ. Siam Soc. Nat. 

 Hist. Suppl., 1931, p. 138 (Doi Suthep). — Chasen and Boden Kloss, Journ. 

 Siam Soc. Nat. Hist. Suppl., 1932, p. 245 (Doi Suthep).— Deignan, Journ. 

 Siam Soc. Nat. Hist. Suppl., 1936, p. 108 (Doi Suthep). 



This form is common on all the mountains of sufficient altitude 

 in the provinces west of (and including) the Khun Tan chain, oc- 

 curring from 3,300 to 5,500 feet, both at the edge of the evergreen 

 and in the open hill-forest. 



It is seen singly or in pairs, silently creeping along a horizontal 

 branch and exploring the underside of the leaves in the deliberate 

 fashion of an American Vireo, or perched upon some exposed twig, 

 turning its head from one side to the other, much like a Tephrodornis. 

 It utters a churring note when alarmed and the pair, when separated, 

 communicate by a sweet double call; de Schauensee states (1929) that 

 it has also "a very pretty warbling song, generally delivered from an 

 exposed and leafless branch at the top of a tall tree." 



An example from Doi Suthep, February 21, had the gonads greatly 

 enlarged. Specimens in postjuvenal molt have been taken between 

 April 24 and July 15 and others in postnuptial molt between May 15 

 and November 4. 



Adults had the irides glaucous-blue, blue-green, olive-green, or 

 brown; the maxilla black, with the commissure edged plumbeous- 

 blue along the basal half ; the entire mandible and the interior of the 

 mouth plumbeous-blue; the feet and toes yellowish fleshy or fleshy- 

 pink ; the soles yellow ; the claws dark horny. 



The old male has the forehead, crown, nape, lores, subocular re- 

 gion, and ear coverts black; a broad white band from above the eye 



