386 My. E, C. Stuart Baker on the Evolution of 



the comparative stupidity or cleverness of the fosterer 

 selected, and this I hope to be able to show conclusively in 

 the following pages. 



I have now for many years past collected eggs of Asiatic 

 Parasitic Cuckoos, and a study of the very many hundreds 

 tliat have passed through ray hands has produced sufficient 

 material to satisfy me on the following points : — 



1. That the eggs of the Parasitic Cuckoos have undergone, 



or are undergoing, a process of adaptation. 



2. That the majority of foster-parents are totalh^ uncon- 



scious of incongruity in size between tlieir own eggs 

 and that of the Cuckoo. 



3. Tliat they are not conscious of variation in shape. 



4. That individuals do detect differences in coloration. 

 The species and the subspecies, the eggs of which have 



passed through my hands, or are now' in my collection, are 

 as follows : — 



Cuculus canorus canorus ; C. c. telephonus ; C. c. hakeri ; 

 C saturatus ; C. jjoliocejihalus; C. micropterus ', Hierococcyx 

 sparveroides ; H. nisicolor ; H. varius; Cacoinantis passerinus \ 

 C. merulinus ; Pcnt/iocery.v sonnerati ; Chrysococcyx a-antho- 

 rliynrhus ; C. macuJatus ; Surniculus luguhris ; Coccystes 

 jacobiims; C. coroinandus ; and Eudynamis honorata. 



As regards Cuculus canorus cmiorus I can add nothing to 

 the mass of information already recorded, nor have I seen a 

 sufficient number of the eggs of C. c. telephoiius to be able 

 to draw any deductions therefrom ; the few I have seen are 

 indistinguishable from many of those of C. canorus canorus. 



Of the next subspecies, however, C. canorus iflAeri, at least 

 a thousand eggs have passed through my hands, and in regard 

 to these it is not difficult to formulate some propositions to 

 which answers can be given. 



Undoubtedly the favourite fosterer to be imposed upon by 

 the Khasia Hills' Cuckoo is the tiny Cisticola cursitans, and 

 of the vast number of eggs laid by C. canorus hakeri in the 

 Khasia Hills probably more than half are deposited in the 

 little ball-shaped nest of grass made by the Fantail Warbler. 

 The fact that this is so would seem at once to go far 



