KHASIA HILLS CUCKOO 97 



Another beautiful type is bright pale blue, often immaculate but 

 sometimes faintly flecked with primary reddish and secondary gray 

 blotches. In the Khasia Hills these are almost invariably deposited 

 in the nests of the silver-eared Mesia or the red-billed Leiothrix (L. 

 lutea calypga) , two species that lay exactly the same type of Qgg to 

 that of the cuckoo, though more boldly blotched, while the two 

 species also make similar nests, which they place in somewhat simi- 

 lar positions in bushes, etc. 



In Burma, more especially in the Ruby Mines district and in the 

 Shan States, we have two dominant types of eggs: One blue, much 

 darker in tint than those referred to as being deposited in Leiothrix 

 nests, laid with the similar eggs of the Burmese dark gray bushchat 

 {Rhodo'phila ferrea haringtoni), and the other having a pale pink 

 ground, freely blotched all over with reddish, deposited in the nests 

 of the Burmese stonechat {Saxicola caprata hurmanica), which also 

 lays eggs of this color and character. In connection with these two 

 types of egg an interesting state of affairs has now been arrived at 

 in parts of the Shan States. Thirty years ago the bushchat was 

 extremely common in certain districts in hills between 4,000 and 

 5,000 feet, and the great majority of cuckoos found there were those 

 laying blue eggs. Cultivation has now wiped out the scrub and 

 bush jungle, beloved by the bushchat, and fields of rice, gardens, and 

 the vegetation surrounding villages have taken its place. With this 

 change in the character of the jungle growth has also come a change 

 in the birds frequenting it, the bushchat has almost disappeared, and 

 the little stonechat has taken its place, breeding everywhere in gar- 

 dens, village grounds, and cultivated fields. The elimination of the 

 bushchat, although so recent, has already gone far to eliminate also 

 the cuckoo that lays blue eggs, while the one that laj^s eggs like those 

 of the stonechat has become much more numerous and has become 

 the common form. Even now, however, an occasional blue egg of 

 a cuckoo will be found in the stonechats' nests, the latter similar 

 in every respect to the nests of the bushchat and therefore cuckolded, 

 faute de 7nieux, by the cuckoo. 



It is impossible here to deal with the problem of the evolution of 

 the various types of cuckoos' eggs, but the facts recorded above seem 

 to go far toward proving that cuckoo eggs, to assimilate with those 

 of their fosterers, have been evolved by discrimination among the 

 foster parents leading to the slow but sure destruction of the unfit, 

 i. e., Darwin's doctrine of the survival of the fittest in its crudest 

 form. 



In shape the eggs are rather broader ovals than those of the Euro- 

 pean cuckoo, and they also average larger and heavier. It is indeed 

 much easier to separate the various subspecies of cuckoo by the eggs 

 they lay than by the plumage of the birds that lay them. 



