194 Major R. F. Meiklejoliii on the [Ibis, 



(15) III placing its egg iu a nest the Cuckoo usually re- 



moves one or more of the eggs of the foster-parent. 



(16) This often occurs a day before the egg is placed iu 



the nest. 



(17) When placing its egg in the nest, or ejecting those 



of the foster-parent, the Cuckoo often has heated 

 struggles with the owners, which frequently result iu 

 the eg^ being destroyed. 



Assigning of Eggs to specific Females. 



Now if the above seventeen conclusions are accepted as 

 correct we have a fairly complete history of the Cuckoo's 

 nesting-habits. I3ut when we review the evidence on which 

 they are based we find they rest mainly on Dr. Key's claim 

 that he was able to assign each egg found to a specific 

 female. We have, therefore, to consider first of all if this 

 claim can be upheld. 



He states that, according to the observations and ex- 

 ])erience of all oologists, it is a rule that not ouly the 

 individual eggs, but also the clutches laid by each female, 

 have a certain distinctive individuality, which can only be 

 explained by certain peculiar conditions in the sexual organs 

 of the female, which enable her eggs to be identified from 

 those of all other females of the same species. Further, 

 that when, in addition to a minute agreement in colour and 

 markings there is also a close resemblance in shape, measure- 

 ment, and weight, it becomes possible, especially in a species 

 like the Cuckoo, whose eggs vary greatly in colouring, to 

 diff'erentiate between those laid by each female. 



Now although great weight must be attached to the 

 statements of such a careful and distinguished observer 

 as Dr. Rey, and admitting that the eggs laid by each 

 female have normally a resemblance to each other in colour 

 and markings, I very much doubt if many oologists will 

 support his claim to be able to assign any egg to a certain 

 female, and this, indeed, is directly contrary to my own 

 experience and that of others. 



