THE BIRDS OF NORTHERN THAILAND 429 



This ground thrush is an apparently rare and local inhabitant of 

 the more western provinces, known only from Doi Khun Tan, 3,000 

 feet, and Doi Suthep, 4,500 feet. The few dated specimens from the 

 North have been taken between May 9 and July 21 and there is just 

 a possibility that the species is present with us only in summer. 



A male collected by de Schauensee on Doi Suthep, 4,500 feet, July 

 21, is in postjuvenal molt. 



The same author states that a male had the irides dark brown; 

 the feet and toes pale yellow. 



The adult male has the entire head and neck and the underparts 

 bright orange-rufous, albescent on the throat and center of the ab- 

 domen and changing to white on the region of the vent and the under 

 tail coverts; the remaining upperparts, including the wings and tail, 

 slaty blue, the feathers of the upper mantle with darker centers, the 

 majority of the remiges with a white area along the inner web near 

 the base; the under wing coverts slaty gray with broad white tips; 

 the axillaries white with broad slaty-gray tips. The adult female 

 differs from the male in having the orange-rufous of the head and 

 underparts rather duller and in having the slaty blue of the upper- 

 parts replaced by olivaceous-brown (changing to slaty on the rump, 

 upper tail coverts, and tail). 



Considerable doubt has been cast by authors upon the distinctness 

 of innotata from citrina, in view of the fact that, in winter, the two 

 forms, together with intermediates, occur together in the Malay 

 Peninsula. I submit that, in so strongly migratory a species, only 

 breeding populations may properly be used as evidence for or against 

 the validity of a given race. Suffice it to say that (1) in the Peninsula 

 we find both citrina and innotata in winter but neither one in sum- 

 mer; (2) all summer-taken birds from any part of Thailand have 

 been innotata. Winter specimens that fall between the two may well 

 have had their origin in geographically intermediate areas. 



The individual from Khun Tan listed (1938) as citrina by Eiley 

 has faintly indicated paler tips to the median upper wing coverts and 

 may be considered a slightly aberrant example of innotata from a 

 locality probably near the periphery of the subspecies' range. 



GEOKICHLA SIBIRICA SIBIRICA (Pallas) 



Siberian Slate-colored Ground Thrush 



Turdiis sibiricus Pallas, Reise durch verschiedene Provinzen des russischen 

 Reichs, vol. 3, 1776, p. 694 ("in syluis alpinis et borealioribus Sibiriae 

 . . ." ; type specimen from tbe Konda river, fide Pallas, ibid., p. 1S6 [where 

 called T. alpinus, nomcn nudum]). 



Oeocichla sibirica sibirica, Rogers and Deignan, Proc. Biol. Soc. Washington. 

 1934, p. 91 (Doi Ang Ka). 



