396 BULLETIN 186, UNITED STATES NATIONAL MUSEUM 



monly between 4,600 and 5,500 feet ; on Doi Suthep once at 3,800 feet 

 (a pair at the Hermit's Cave, March 7, 1931) ; on Doi Chiang Dao 

 twice, at 3,000 and 5,000 feet; on Phu Kha once at about 4,500 feet; 

 at Ban Huai Ki once in lowland evergreen. 



On Doi Ang Ka I watched it climb silently about fallen trees and 

 investigate crannies and crevices in the rocks, acting quite like other 

 members of the genus. A flock of five or six individuals observed by 

 Gyldenstolpe at Doi Pha Sakaeng communicated with each other by 

 faint whistling notes. 



Examples with the gonads enlarged were taken on Phu Kha, April 

 12, and on Doi Ang Ka, April 22 and 26 ; at the latter locality, a bird 

 in postnatal molt was collected April 22 and another in postnuptial 

 molt, September 5. 



Males in breeding condition had the irides brownish red or red- 

 brown ; the maxilla blackish brown, tipped dark gray ; the mandible 

 brown, horny at the base, or plumbeous-gray, gray- white at the base ; 

 the tarsi fleshy brown or horny brown ; the toes brown or horny brown 

 with a fleshy tinge ; the claws fleshy horn or horny brown. A juvenile 

 female had the irides dull brown ; the maxilla blackish brown with the 

 extreme tip yellow ; the mandible with the anterior half dark brown, 

 the rest fleshy ; the rictus and interior of the mouth yellow ; the tarsi 

 fleshy brown ; the toes dark brown ; the claws horny brown. 



The adult has the upperparts dark olivaceous-brown, changing to 

 dark rufous-brown on the rump, upper tail coverts, and tail, the 

 feathers of the crown and upper half of the back with conspicuous 

 brownish-ashy centers and fairly broad blackish margins ; the upper 

 wing coverts and most of the remiges with small, but distinct, white 

 or brownish- white tips; the lores, indistinct supercilium, and sides 

 of the head dark ashy ; the feathers of the chin and throat ashy, with 

 dark brown central streaks; the remaining underparts ferruginous, 

 paler on the center of the breast and belly, deeper along the flanks and 

 on the under tail coverts. 



I find so much variation in coloration and length of wing among 

 even a small series of Thai birds that it seems to be impossible at present 

 to recognize more than one race from our area. The two specimens 

 from Doi Chiang Dao and one from Doi Langka are more saturate 

 throughout than true brevicaudata and thus approach venningi, which 

 will probably prove to be the form of Doi Pha Horn Pok; in wing 

 length, on the other hand, they agree well with Tenasserimese birds. 

 The single example from Ban Huai Ki appears to be different from 

 that of Phu Kha and fits the description of proximo, (Bas-Laos) ; it is, 

 however, badly worn (June 23) and can be matched perfectly with 

 certain Tenasserimese skins. 



