THE BIRDS OF NORTHERN THAILAND 79 



at Chiang Mai, on Doi Suthep, along the Mae Sa river (about 15 km. 

 northwest of Chiang Mai) , at Wiang Pa Pao, and at Muang Ngop and 

 have observed it at many other localities. 



This magnificent eagle may be seen quietly perched in a tree at the 

 edge of a path or clearing in the jungle, but it spends much of its time 

 wheeling high in the air above fhe forest canopy, its presence made 

 known by a characteristic plaintive scream, which can be heard even 

 when the bird (or birds, for they are usually in pairs) is invisible in 

 the sky. 



The stomach of one of my specimens, taken on Doi Suthep, con- 

 tained crabs and a small snake ; the latter has been identified by Dr. 

 Doris M. Cochran, of the U. S. National Museum, as Simotes (Holar- 

 chus) violaceus. 



A male taken by me at San Sai Luang, near Chiang Mai, February 

 27, had the gonads slightly enlarged. 



Birds taken in July were found to be in molt. An adult of July 6 

 has the second primary largely ensheathed, one central rectrix half- 

 grown, the other somewhat shorter. An adult of July 27 has the first 

 primary only half-grown. 



Adult examples had the irides golden-yellow; the lower eyelid 

 livid white, edged bright yellow ; the upper eyelid, orbital region, lores, 

 rictus, and cere bright yellow ; the bill plumbeous with the apical half 

 black ; the feet and toes yellow ; the claws black. 



This is one of the most easily identifiable of our large hawks. When 

 a perching individual is alarmed, the crest is erected so as to frame 

 the face with a beautiful black and white ruff. From below, a flying 

 bird may be known at once by the broad whitish bar, edged by two 

 black bands, across the primaries, and by the broad whitish bar across 

 the middle of the blackish tail. 



The adult has the crown and a full, rounded nuchal crest black, 

 with the basal half of each feather pure white, these bases showing 

 through in places when the crest is not raised ; the upperparts dark 

 brown; the coverts along the forearm with small white spots, the 

 other coverts like the back; the visible portion of the tail feathers 

 black, with the base brown, a broad band across the center brownish 

 white, the extreme tip whitish ; the throat and sides of the head gray- 

 ish brown ; the remaining underparts brown, with blackish-bordered 

 white ocellations on the abdomen, changing to bars on the thighs 

 and under tail coverts ; the primaries black, with a broad gray-brown 

 band near the end and two other gray-brown bands near the base, 

 these mottled with white on the inner web; the underwing broadly 

 barred black and white. The immature is quite different : it has the 

 feathers of the crown and crest fulvous-white with a blackish-brown 

 subapical bar ; the upperparts brown, each feather brownish white at 



