THE BIRDS OF NORTHERN THAILAND 433 



subspecies it is not separable by color but may be known by its longer 

 wing tip and generally greater dimensions : whereas the wing length 

 of dauma ranges from 138 to 146 mm., that of aurea ranges from. 152.6 

 to 168.5 mm. (8 specimens of the former, against 26 of the latter). 



The male from Kengtung Town, recorded (1934) by de Schauensee 

 as aurea, is, in my opinion, an example of dauma with 14 rectrices. 



ZOOTHERA MARGINATA PARVA Delacour and Jabouille 



Indo-Chinese Lesser Long-billed Thrush 



Zoothera marginata parva Delacour and Jabouille, L'Oiseau et la Revue Fran- 

 chise d'Ornithologie, vol. 11, 1930, p. 397 (Long-Phinh, Pakha, Tongking). 



Zoothera marginata, Deignan, Journ. Siani Soc. Nat. Hist. Suppl., 1935, p. 65 

 (Doi Ang Ka). 



Zoothera marginata marginata. Deignan, Journ. &iam Soc. Nat. Hist. Suppl., 

 1936, p. 113 (Doi Suthep). 



Zoothera marginata parva, Gkeenway, Bull. Mus. Cornp. Zool., 1940, p. 181 (Doi 

 Ang Ka, Doi Nang Kaeo). 



This long-billed thrush is apparently, if not actually, a very rare 

 bird in northern Thailand : it has been taken on Doi Nang Kaeo at 

 2,800 feet; on Doi Suthep (once) at 3,500 feet; on Doi Ang Ka at 

 various elevations between 4,600 and 8,400 feet on Doi Pha Horn Pok 

 at 6,400 feet. 



It is a shy species of dense, moist evergreen forest, where it keeps to 

 the ground and probably is often overlooked in the darkness of the 

 undergrowth. A clew to its real numbers is given by the fact that, on 

 Doi Ang Ka, 4,600 to 4,800 feet, between September 4 and 7, 1935, 1 saw 

 no less than six juveniles, four of which were easily collected ; these 

 examples drew attention to themselves by their reiterated alarm note : 

 pit-pit-pit. 



In three of my specimens postjuvenal molt is just beginning, while 

 in the fourth it is far advanced. 



The adult has the crown and nape deep olivaceous-brown, the feath- 

 ers indistinctly edged darker; the mantle rufous-brown, the feathers 

 similarly margined; the wings rufous-brown, most of the remiges 

 with a buffy-white area along the inner web toward the base, the upper 

 coverts narrowly tipped with rufous-buff ; the tail rufous-brown ; the 

 sides of the head and neck mixed buffy white and deep olivaceous- 

 brown ; the chin and throat white, many of the feathers with blackish- 

 brown tips, these tips larger at each side of the throat to form a poorly 

 defined mustachial line ; the feathers of the breast buffy white, broadly 

 margined (especially at the sides) with olivaceous-brown, those of 

 the flanks olivaceous-brown with buffy-white shaft streaks, those of 

 the belly white with posteriorly obsolescent olivaceous-brown crescentic 

 tips; the under tail coverts olivaceous-brown, with buffy-white mar- 



