55 [Vol. xliii. 



tliey are being built, and usually in the very early stages, 

 and indeed lays each egg because she conceives it upon a 

 specific nest which is under construction, then it logically 

 follows that it is a matter of indifference to the Cuckoo as to 

 the contents of the nest when she does lay, but the egg will 

 be laid after the foster-bird has herself begun to lay, for the 

 reason that the Cuckoo follows the foster-bird in her con- 

 ception of laying. Equally obviously, the Cuckoo will lay 

 her own egg whilst the other eggs are still fresh if it takes 

 a Cuckoo no longer to produce her egg than it does the 

 foster-bird ; much as I should like to, however, I must not 

 go into too much detail. 



Drawer 4 contains only the eggs taken on, and in the 

 immediate vicinity of, another Common three miles distant 

 from the Common which is the habitat of Cuckoo "A." 

 This drawer contains just half-a-dozen casually collected 

 eggs in the year 1920, as against what we believe to be the 

 whole of all the Cuckoos' eggs laid on that Common the 

 next year, 1921, with the exception of three eggs which we 

 left to hatch for photographic purposes. " Mary Pickford " 

 is the dominating Cuckoo here, and drove off in turn last 

 season no less then four other Cuckoos, which between them 

 laid fewer eggs than she did. 



There is a fund of information provided in a close study of 

 these drawers by a careful student. Proof of the attacks 

 made upon the Cuckoos by the irate foster-parents is to be 

 found in the feathers exhibited, which were seen to be 

 plucked from the Cuckoos. The four cases in which " Mary 

 Pickford" and another Cuckoo were persuaded to lay in 

 substitute nests (thanks to the ingenuity of my friend, 

 Mr. Smyth) are illustrated in Drawer 4. 



A collective study of Drawers 1, 2, and 4 also raises 

 serious doubts in one's mind as to whether males do really 

 outnumber females. My theory of dominating Cuckoos 

 versus those unable to hold a territory is also admirably 

 illustrated. 



Drawer No. 3 contains some interesting specimens of 

 Cuckoos' eggs taken during recent years by my friend 

 Mr. 0. R. Owen, of Knighton. There is also in this drawer, 



