5(3 SPIZAETUS CETLONENSIS. 



Mature bird. At about three or four years of age, in a stage of plumage in which most dark birds are met with, the head 

 and hind neck are more or less sienna-brown, with the centres of the feathers blackish, least so on the hind neck ; on 

 the forehead and above the lores the narrow feathers are pale-edged ; crest, which is sometimes IJ inches in length, 

 black, conspicuously tipped with white, the shorter feathers being blackish brown, paling into rufous at tin- white 

 tips ; back, scapulars, and wing-coverts deep glossy brown, paling off at the margins into a tawny hue, the greater 

 coverts with less of the dark brown central hue, finely edged gre)dsh, and with the concealed portions of the bases 

 white; winglet and primary-coverts, the quills and secondaries dark brown, barred and terminated with black. 

 much as in the above, but with more white on the inner webs, and with the tips of the secondaries whitish, a 

 fulvous patch on the outer webs of the longer primaries opposite the notch; tertials wood-brown, paler than the 

 scapulars : rump and upper tail-coverts of a similar hue ; tail smoky brown, tipped white and crossed with four 

 blackish bands, the subterminal one equal in width to the preceding interspace, the next two much narrower, and 

 the basal one generally incomplete ; on the lateral feathers there is au additional pale basal bar, and the inter- 

 spaces are mottled with white. 



Cheeks and the sides of the neck beneath them boldy streaked with blackish, the edges of the feathers being while ; 

 ear-coverts concolorous with the hind neck. Chin, throat, and under surface white, contracted at the centre of 

 the fore neck between the tawny hue of its sides ; a narrow blackish-brown chin-stripe passing down to the chest 

 from which to the abdomen each feather is centred with a broad drop-shaped dash of blackish brown ; on the 

 abdomen and flanks these expand until they cover the terminal portion of the feathers ; the lower flank-plumes 

 blackish brown, forming a large dark patch ; under tail-coverts dark brown, usually tipped with white ; thighs 

 and upper part of tarsus a more rufous-brown, paling into buffy white at the feet ; under surface of tail and of 

 the quill-interspaces whitish ; bases of quills beneath pure white ; under wing-coverts white, dashed and striped 

 in places with blackish brown, those beneath the ulna centred widely with rufous-brown. 



In these birds I have invariably found the iris yellow, which is the normal colour, I imagine, of the eye in the adult. 



Young*. Nestling clothed with white down, with the crest-feathers plainly indicated by three or four attenuated 

 downy shafts ; the wing-coverts, scapulars, and quill-feathers on first appearing are fulvous-brown, deeply tipped 

 with white : the tail-feathers are similar, and the whole darken considerably in a short time, the hue of the inter- 

 scapular feathers being deeper than that of the rest. 



Nestling plumage at 3 months. Iris leaden grey ; bill dusky plumbeous, blackish at the tip ; feet light lemon-yellow. 



Head, back, and sides of neck with the ear-coverts light sienna-brown, edged with whitish : crest-feathers blackish, 

 deeply tipped with white ; back, scapulars, and lesser wing-coverts dark sepia-brown, the scapulars broadly tipped 

 with white, and the back feathers margined, terminally, with rufous-grey, the bases being paler brown than the 

 rest; median wing-coverts mostly white, with a longitudinal patch of brown; greater series broadly margined 

 with white, the outer webs being a paler or fawn-brown ; primaries and secondaries brown, the former the darker 

 in hue, tipped with white and crossed with narrow bars of black, vanishing near the internal edges, which are 

 white ; first primary and terminal portion of the long ones almost uniform blackish ; rump aud upper tail-coverts 

 fawn-brown ; tail umber-brown, with a deep white tip and five or six narrow bars of blackish brown, the sub- 

 terminal one slightly broader than the others, and the light interspaces, as in the quills, showing white beneath. 



A thin white line from nostril over the lores; loral plumes blackish ; lower part of cheeks, throat, and under surface 

 pure white, dashed on the sides of the chest and breast with light sienna-brown " drops," those on the flanks 

 being slightly darker and coalescing into a patch at the lower part; belly, thighs, and under tail-coverts dashed 

 with pale brown and tipped with white; tarsi white. The extent to which the under surface is marked in this 

 stage varies. The " drops, - ' however, darken after the space of two months, as do also the feathers of the head 

 aud hind neck, which at the same time acquire darker mesial stripes ; the brown of the back and wings also 

 becomes more intense, and the bird is then in the normal plumage of the first year, with a long crest measuring 

 from 3 to 4 inches. 



At the second .moult the example under consideration darkened on the head and hind neck, the crest remaining the same : 

 the white of the wing-coverts diminished in extent, and the tail underwent a considerable change, the number of 

 bars on the central feathers being reduced to four of greater width than the last, especially the terminal one, which 

 was preceded by an equally broad interspace, the chest " drops " increased in number and in intensity, and the 

 lower parts became more covered with brown ; the dark patches on the white under wing-coverts were also more 

 numerous. 



These changes of plumage are described from observation, during youth, of the above living example, as well as 

 from notes on other immature birds in my collection. 



