CUCKOO. 385 



the sexes is much greater; the male loses nearly all the chestnut on his 

 plumage^ but retains the white edges to the feathers^ whilst the female 

 moults into what is called the " hepatic " stage, in which the chestnut is 

 increased in brilliancy and the white edges to the feathers disappear. 

 These females just entering their second year do not breed, and seldom 

 migrate far north — a fact which may be observed in many other species. 

 In the following autumn both male and female assume nearly adult 

 plumage, traces of immaturity being still found, especially in the female, 

 on the breast and back. The fully adult plumage is assumed in the 

 following spring, when the bird is scarcely two years old. In this plumage 

 the general colour of the upper parts is slate-grey, browner on the wings, 

 which are barred on the inside webs with white, and nearly black on the 

 tail, which is broadly tipped with white and shows obscure traces of white 

 bars, which, however, are often absent on the centre feathers. The general 

 colour of the underparts above the breast is pale slate-grey, and below 

 greyish white, with dark-brown transverse bars, which become very indis- 

 tinct on the under tail-coverts. In immature birds the chin and throat 

 are barred like the breast. Bill slaty black, paler at the base and yellow 

 at the edges ; legs, feet, and claws orange-yellow ; orbits and irides yellow. 

 In the fully adult plumage the sexes are alike in colour. 



VOL. Ti. ^^ 



