260 BULLETIN 186, UNITED STATES NATIONAL MUSEUM 

 CORYDON SUMATKANUS LAOENSIS de Schauensee 



Thai Dusky Broadbill 



Corydon sumatranus laoensis de Schauensee, Proc. Acad. Nat. Sci. Philadelphia, 

 vol. 80, 1928 [=1929], p. 555 ("The Siamese Lao"; type specimen from D,oi 

 Suthep, fide de Schauensee, Hid., p. 571). 



Corydon sumatranus, Gyldenstolpe, Journ. Nat. Hist. Soc. Siam, 1915, p. 229 

 (Khun Tan) : Kungl. Svenska Vet.-Akad. Handl., 1916, p. 87 (Pha Kho, 

 Khun Tan) ; Ibis, 1920, p. 582 (Pha Hing, Khun Tan). 



Corydon sumatranus laoensis, de Schauensee, Proc. Acad. Nat. Sci. Philadelphia, 

 1928, p. 571 (Doi Suthep).— Riley, U. S. Nat. Mus. Bull. 172, 1938, p. 247 

 (Doi Ang Ka, Khun Tan, Huai Salop, Thattafang). 



Corydon sumatranus sumatranus, de Schauensee, Pr,oc Acad. Nat. Sci. Phil- 

 adelphia, 1929, p. 565 (Chiang Saen). 



Corydon corydon laoensis, de Schauensee, Proc. Acad. Nat. Sci. Philadelphia, 

 1934, p. 245 (Doi Chiang Dao). — Deignan, Journ. Siam Soc. Nat. Hist. 

 Suppl., 1931, p. 156 (Doi Suthep) ; 1936, p. 98 (Doi Suthep). 



The dusky broadbill is fairly common in the unsettled districts of 

 all the northern provinces from the plains to a maximum elevation of 

 3,300 feet, On Doi Suthep (the type locality) it is distinctly rare, 

 and I recorded it there only twice: Two at 2,500 feet, October 10, 



1936, and two at 3,300 feet, January 23, 1937. 



This large species haunts, in fearless flocks of as many as 20 indi- 

 viduals, both the more open evergreen and the mixed-deciduous forest, 

 and behaves much as other members of its family. Gyldenstolpe 

 observes (1916) that the clear whistling note is given only during 

 flight from tree to tree, the carrying croaking note while the bird is 

 at rest. 



I took a male with enlarged gonads at Ban Huai Ki, March 28, 



1937. De Schauensee, speaking of his original series (taken March 

 17, 1928), says: "We saw about ten of these birds, all apparently en- 

 gaged in building the same nest. They were going in and out of a 

 hole in the side. The nest was collected but was unfortunately not 

 completed." Eight adults taken by me between May 24 and December 

 8 are in postnuptial molt. 



My specimens had the irides dark brown; the orbital region rose; 

 the bill rose, the tip and the edges of the commissure plumbeous-blue; 

 the feet, toes, and claws brownish black. 



The adult has the throat and upper breast fulvous-white, each 

 feather narrowly margined with deeper fulvous ; each primary with a 

 broad band of white near the center; the rectrices (except the two 

 central pairs) crossed by a diagonal, subterminal white bar; a flame- 

 colored patch at the center of the back (usually concealed in life) ; 

 the rest of the plumage black, faintly suffused with oily green, 

 especially on the underparts, rump, and upper tail coverts. 



De Schauensee believed (1929) that the birds of Doi Suthep dif- 

 fered subspecifically from other northern examples in their whiter 



