BORNEAN CRESTED FIREBACK 



141 



full grown but unshed. The outer secondary is still unshed ; the second is full grown. 

 The next five are new, more recent as we proceed inward, until the fifth is merely a 

 short unbroken sheath ; the next inner six are unshed. 



The persistence of the first secondary is very remarkable. Not only in these birds, 

 but in another of seven months, which in many respects is full plumaged, the right 

 outer secondary still persists, the left having just been shed. The succeeding nine 

 secondaries are full grown, the next three being, like No. i, still old, unshed 

 feathers. 



Another focus of delayed growth is found in the central rectrices. In the three 

 males just described, the three inner pairs of tail-feathers are still unshed, juvenile 

 feathers, although all of the others are new and well advanced. In all there is a 

 regular gradation in growth from the outer to the fifth pair, the latter being only 

 25 or 30 mm. beyond the tip of the sheaths. The narrow, brown, worn tips of the 

 three inner pairs extend some 50 mm. beyond the longest new feathers, giving all 

 the birds a most curious appearance. At this age the spurs are about 5 mm. in length, 

 sharp, thin, triangular scales. 



The measurements of the five stages of growth in male birds which I have 

 described, together with those of the adult male are as follows, tabulated for easier 

 comparison. 



Four day chick .... 

 Three weeks chick . 

 Seven weeks juvenile 

 Older full juvenile . 

 Transitional, juvenile to first year 



Adult male .... 



Bill from 

 nostril 



Wing 



6 



20 



8 



78 



II 



129 



15 



210 



18 



235 



21 



271 



Tail 



Tarsus 







23 



10 



25 



66 



35 



137 



68 



Juv. 168 



86 



New 127 





(Not full grown) 





253 



III 



Middle Toe 

 and Claw 



16 

 18 



25 

 46 



51 



58 



Immature Female. — The sexes are well marked first in the early juvenile plumage 

 when the mantle and breast begin to show a preponderance of dark colour in the male, 

 or rufous in the female. The head, nape, mantle and lower throat in the latter sex 

 moult into almost solid chestnut, shading into white on the upper throat and chin. 

 The black ocelli or sub-terminal band on the scapulars and wing-coverts are much 

 more conspicuous than in the male, owing to their pale, rich chestnut setting. The 

 secondaries also show the chestnut mottling much plainer in the female sex. 



The ventral surface of the immature female is more definitely coloured, the regular 

 pattern showing dark brown centres, broad white lateral fringes and an equally 

 well-marked terminal band of chestnut. This pattern extends well down the sides 

 of the body, but on the lower breast the white begins to eclipse all other hues, until 

 on the belly it wholly replaces them. 



One young female shows the inner six pairs of rectrices still unshed, while the 

 two outer pairs are represented by tiny sheaths. In another the three central pairs 

 are still unshed. All show the same gradual moult from outside inward as in the 

 males. 



