THE BIRDS OF NORTHERN THAILAND 77 



examined usually contained frogs, but once a small snake and once 

 a munia (Lonchura sp.). 



Specimens taken in Thailand show no gonadal activity. In at least 

 some cases, the female of this species has paired ovaries. 



An immature male, taken at Chiang Mai, January 14, is acquiring 

 the central tail feathers of the adult ; they are about four-fifths grown. 

 An adult female from Ban Mae Chai Tai, December 27, has also 

 molted the central rectrices: one of the new feathers is about four- 

 fifths grown, the other one-half. 



I have noted that an adult male had the irides dark brown ; the bill 

 brownish black; the feet and toes chrome-yellow. De Schauensee 

 records that an immature male had the irides light yellow ; the cere 

 olive-yellow ; the bill black, gray at the base ; the rictus green above, 

 blue below ; the interior of the mouth dark slaty blue ; the feet and toes 

 bright yellow ; the claws black. 



The adult male is an unmistakable bird, with the head, throat, 

 breast, back, outer scapulars, quills, and median upper wing coverts 

 black; the rump and a large shoulder patch grayish white; the tail, 

 inner scapulars, and greater wing coverts silvery gray ; the underparts 

 pure white ; the under wing coverts white, the remaining underwing 

 black. The adult female has the upperparts brown, streaked on the 

 head and the coverts along the forearm with rufous and white; the 

 upper tail coverts white with rufous-brown markings along the shafts ; 

 the tail crossed by about five darker brown bars ; the underparts white, 

 heavily streaked with brown. Immature birds are dark brown above, 

 with the upper tail coverts white, marked with brown ; dark brownish 

 rufous below. 



CIRCUS AERUGINOSUS AERUGINOSUS (Linnaeus) 



Western Marsh Harrier 



[Falco] aeruginosus Linnaeus, Systema naturae, ed. 10, vol. 1, 1758, p. 91 

 (Europe; type locality restricted to Sweden, apud Hartert). 



Circus aeruginosus, de Schauensee, Proc. Acad. Nat. Sci. Philadelphia, 1929, p. 

 579 (Chiang Mai). 



Circus aeruginosus aeruginosus, Deignan, Journ. Siam Soc. Nat. Hist. Suppl., 

 1931, p. 166 (Chiang Mai) ; 1936, p. 77 (Chiang Mai). 



An undated female specimen in Stockholm was taken by Eisen- 

 hof er at Khun Tan ; otherwise the only definite records for our area are 

 based upon a female collected by de Schauensee at Chiang Mai, De- 

 cember 25, 1928, and two specimens taken by me at the same locality, 

 December 5, 1931. The species is only a winter visitor to northern 

 Thailand, where it probably occurs in small numbers in all the 

 provinces. 



My specimens, which I supposed to be immature Brahminy kites, 

 were taken on one of the large marshes south of Chiang Mai. The 



