10 BIRDS OF BRITISH BURMAH. 



409. COLLOCALIA LINCHI. 



HORSFIELD'S SWIFTLET. 



Hirundo fuciphaga, apud Horsf. Trans. Linn. Soc. xiii. p. 143. Collocalia 

 linchi, Horsf. $ Moore, Cat. Birds Mus. E.I. Co. i. p. 100 ; Wallace, P. Z. S. 

 1863, p. 384 ; Hume, S. F. ii. p. 157 ; id. Nests and Eggs, p. 89 ; Salvad. Ucc. 

 Born. p. 121 ; Hume fy Dav. 8. F. vi. p. 49 ; Hume, S. F. viii. p. 85. Col- 

 localia affinis, Tytler, Beavan, Ibis, 1867, p. 318. Collocalia fuciphaga, 

 apud Bl. fy Wald. B. Burm. p. 85. Collocalia francica, apud Legge, Birds 

 Ceylon, p. 324. 



Description. Male and female. Plumage above entirely glossy bronze- 

 black ; chin, throat, breast,, sides of the head and sides of the body ashy 

 brown, each feather obsoletely margined paler; abdomen and vent white 

 streaked with brown ; under tail- coverts dark brown, margined with white ; 

 wings and tail glossy black. 



Length 4 inches, tail 1'75, wing 4, tarsus '3, bill from gape '4. The 

 female is of about the same size. 



Mr. Blyth recorded two species of Swiftlets from Burmah (B. Burm. 

 p. 85) . The one which he calls C. fuciphaga he identifies with Mr. Ball's 

 bird, which that gentleman describes in the J. A. S. Beng. xli. p. 276, and 

 again in ' Stray Feathers/ i. p. 55. Although Mr. Ball speaks of an indis- 

 tinct white rump-band, no one can entertain any doubt about his birds 

 being the true C. linchi. I accordingly enter this species here, more espe- 

 cially as it is very abundant in the Andaman Islands, and is consequently 

 pretty certain to fly over to the Burmese coast. 



C. esculenta, a bird from Java and the Malay archipelago, is very close 

 to C. linchi both in size and coloration ; but it may be known at once by 

 its having white spots on the tail-feathers. 



Another section of Swiftlets may be recognized by the rump being pure 

 white. None of them are, however, likely to visit Burmah. 



After studying a large series of birds of the genus Collocalia, I am of 

 opinion that the plumage is liable to very slight variations only. In the 

 adults the coloration is very constant; and the young differ from the 

 adults only in being paler. The confusion which has hitherto existed 

 among the members of this group appears to be due in great measure to 

 the paucity of specimens in European collections. Mr. Hume has 

 rendered great service to ornithologists in thoroughly working out the 

 Indian members of the group. 



Horsfield's Swiftlet occurs, according to Mr. Blyth, in Arrakan and 

 Tenasserim ; but Mr. Davison did not meet with it during his travels in 

 the latter Division. 



It occurs very abundantly both in the Andaman and the Nicobar 

 Islands. 



