THE BIRDS OF NORTHERN THAILAND 319 



concealed portions of the remiges black, the outer webs of most of the 

 primaries narrowly edged along part of their length with sky blue ; 

 the ear coverts pale violet ; the throat white, changing to pale violet- 

 vinaceous on the breast and abdomen and to violet-gray on the under 

 tail coverts. The adult female differs in having no black supercilium. 

 Juveniles have the black frontal patch less distinct; the breast and 

 abdomen suffused with buff; the under tail coverts indefinitely barred 

 with gray or white and pale buff. 



The wing lengths of 16 northern males range from 74 to 78 mm. 

 and in only four cases does this measurement exceed 76 mm. 



Family CERTHIIDAE 



CERTHIA DISCOLOR SHANENSIS Stuart Baker 



Shan Brown-throated Tree Creeper 



Certhia discolor shanensis Stuaet Baker, Fauna of British India, Birds, ed. 2, 

 vol. 8, 1930, p. 617. New name for Certhia discolor fuliginosa Stuart Baker 

 1922 (Loi Pang Nan [Southern Shan States]), not C[erthia] fuliginosa 

 Bechstein, 1811. 



Certhia discolor manipurensis, de Schauensee, Proc. Acad. Nat. Sci. Philadel- 

 phia, 1929, p. 541 (Doi Suthep). — Deignan, Journ. Siam Soc. Nat. Hist. 

 Suppl., 1931, p. 141 (Doi Suthep). 



Certhia discolor shanensis, Chasen and Boden Kloss, Journ. Siam Soc. Nat. 

 Hist. Suppl., 1932, p. 247 (Doi Suthep).— Deignan, Journ. Siam Soc. Nat. 

 Hist. Suppl., 1936, p. 104 (Doi Suthep).— -de Schauensee, Proc. Acad. Nat. 

 Sci. Philadelphia, 1934, p. 207 (Doi Suthep).— Riley, U. S. Nat. Mus. Bull. 

 172, 193S, p. 316 (Doi Ang Ka, Doi Langka). 



The brown-throated tree creeper, restricted in Thailand to deep 

 evergreen forest at elevations above 4,500 feet, has been found with us 

 only on the three peaks listed above. On Doi Suthep it is not uncom- 

 mon from 4,500 to 5,000 feet ; on Doi Ang Ka it is common from 4,900 

 to 6,000 feet, somewhat less so up to 8,000 feet. 



In the greenish half-light of moss-draped cloud-forest, the soft seep 

 of the tree creeper is one of the few sounds to break the silence at the 

 foot of the trees. When hanging motionless against a tree the little 

 bird is scarcely distinguishable from an excrescence of bark ; recovered 

 from its alarm, however, it ascends the trunk with quick, jerky move- 

 ments, describing a wide spiral until the branches are reached, from 

 which point it drops rapidly to the base of another tree and begins 

 again its upward spiral. From March to June may be heard the ring- 

 ing song: a rather loud chee-weet, chee-weet, chee-weet, chee-weet, 

 with the weet accented. 



A male from Doi Suthep, 5,100 feet, March 12, had the gonads 

 greatly enlarged. An example from Doi Ang Ka, May 4, has almost 

 completed the postnatal molt and two adults from the same mountain, 

 September 3, are in postnuptial molt. 



