THE BIRDS OF NORTHERN THAILAND 189 



January 16, 1933, and I shot one at the same spot, March 19, 1937. 

 On Doi Suthep it occurred irregularly throughout the year from 

 3,300 to 5,500 feet and was seen once or twice over the lowest slopes 

 of the mountain. 



This is a difficult bird to collect, owing to its small size, darting flight, 

 and the forested or precipitous nature of its habitat; I was able to 

 take specimens only on the few occasions which I happened to be on 

 some treeless ridge or hilltop just as a loose flock passed by at a 

 comparatively low altitude. On Doi Ang Ka it was often associated 

 with Apus a subfurcatus, on Doi Chiang Dao and Doi Suthep with 

 Riparia c. sintaungensis. Stomachs I examined were filled with 

 minute insects. 



My specimen of March 19 had the testes greatly enlarged, but the 

 birds taken April 20 had the gonads quite inactive. 



This swift has the irides dark brown; the bill black; the interior 

 of the mouth dusky fleshy; the tarsi brownish pink; the toes dark 

 brown; the claws black. De Schauensee records that his example 

 had the feet and toes purplish. 



The present species might be confused only with the palm swift 

 of the lowlands; from the latter it may be known by its slightly 

 greater size and by its having a noticeable gray band across the 

 rump. 



Dr. Ernst Mayr, who has made an intensive study of this difficult 

 genus, kindly identified my specimens, in 1932 and again in 1939, as 

 innominata. 



For use of the names Chaeturiformes and Chaeturidae, see Brod- 

 korb, Wilson Bull., 1940, p. 214. 



CHAETURA GIGANTEA INDICA Hume 



Indian Brown-throated Spine-tailed Swift 



Chaetura indica Hume, Stray Feathers, vol. 1, 1873, pp. 471-474 ("Andamans and 



various parts of Southern India"). 

 Chaetura gigantea indica, Gyldenstolpe, Kungl. Svenska Vet.-Akad. Handl., 



1913, p. 56 (Mae Raem) ; Ibis, 1920, p. 584 (Mae Raem, Pha Kho, Huai San 



Noi). 

 Chaetura sp., Gyldenstolpe, Kungl. Svenska Vet.-Akad. Handl., 1916, p. 106 ( Huai 



San Noi, Pha Kho). 

 Eirundapus giganteus indicus, Deignan, Journ. Siam Soc. Nat. Hist. Suppl., 1931, 



p. 163 (Doi Suthep) ; 1936, p. 91 (Doi Suthep) —Riley, TJ. S. Nat. Mus. Bull. 



172, 1938, p. 160 (Khun Tan). 



This giant swift is a rather common winter visitor throughout our 

 provinces. On Doi Suthep it was normally seen only above the 

 highest ridges (5,500 feet) but at least once (January 2, 1937) was 

 found with Apus p. cooki as low as 2,800 feet. Gyldenstolpe twice 

 saw it flying up and down small lowland streams at dusk. I myself 

 observed great numbers of migrating birds flying just above the leaf- 



