53 [Vol. xliii. 



for her consistently to sit for anything like one to three 

 hours concentrating her attention upon the victim's nest, for 

 if she regurgitates the egg she must have it in her gullet or 

 crop all this while. Remember that we have watched this 

 business now during the last two seasons on over twenty 

 occasions, whereas it is a fact that no one else has ever 

 watched it once in similar fashion. By " watching," I mean 

 finding the Cuckoo hours in advance of the time at which we 

 know she is .going to lay, and keeping that Cuckoo under 

 absolutely continuous observation without even a second's 

 break for the whole period, no matter whether it be for one 

 hour or three hours, until the Cuckoo flies down to lay. In 

 no case does she fly down meanwhile and settle on the 

 ground, and therefore, according to our friends, the Cuckoos 

 we have watched must have laid hours previously and are 

 content to sit and fly about all that time with eggs either 

 in their throats or anywhere else except where an egg is 

 understood to be before it is laid, and all tiiis without 

 showing the slightest desire to get rid of the egg earlier ! 



Mr. Baker appears to find difficulty in believing that a 

 Cuckoo can lay within eight seconds, and yet hold the egg 

 up for hours (not only half an hour) if compelled to do so. 

 I suggest to you that evolution has compelled Cuckoos to 

 acquire this faculty, and that is probably why Cuculus canorus, 

 at any rate, lays such a very small egg in comparison with 

 her size. 



I will now pass on to the other equally interesting Cuckoo 

 problems by referring you to my exhibits. 



In passing, permit me to express the opinion that very 

 much safer deductions may be drawn from a close study of 

 Cuckoos' eggs, collected in the systematic fashion which we 

 have adopted, than of eggs which have been casually 

 collected and selected. For example, if a man shows you 

 one or two eggs only out of each season's laying by one 

 Cuckoo, and can exhibit illustrations of such selected 

 Cuckoos* eggs being laid in the nests of different species of 

 fosterers, and thereby argues that the Cuckoo does not show 

 any marked preference for any particular foster-bird, it is 

 obvious that he is basing his conclusions on entirely in- 



