Birds of Britain 



vorous birds are made use of as foster-parents, and there 

 is no doubt that much discrimination is exercised by the 

 mother Cuckoo as to where and when to deposit her 

 egg. The nests most favoured in this country are those of 

 the Meadow Pipit, Pied Wagtail, Hedge Sparrow, Sedge 

 and Eeed Warblers, but over sixty different species of 

 British Birds have been made use of at various times. 

 Practically nothing is known as to whether Cuckoos pair, 

 or if the female receives the attentions of several males, 

 and the number of eggs laid by a single bird in the season 

 is also doubtful, though about eight is said to be the 

 number. Many interesting problems are thus still un- 

 solved about one of our commonest birds, and if his 

 character be not a very estimable one, we can but marvel 

 at the workinsjs of evolution which has enabled so curious 

 and complicated a method of parasitism to be sufficiently 

 successful to ensure the perpetuation of the race. It must 

 be remembered that for the successful rearing of each young 

 Cuckoo the mother has to find and recognise the nest of an 

 insectivorous bird, and to lay her egg during the five days 

 in which the foster-parent elect is laying her clutch. As 

 regards the various stagjes of evolution that have caused 

 the young Cuckoo to evolve as a murderer at his birth, and 

 that have provided him with the means in the shape of a 

 special hollow in his back, we know nothing, and can in 

 the present state of our knowledge merely leave the 

 problem in wonder and amazement. 



The male is clear greyish ash on the back and throat ; 

 tail feathers blackish with small white spots on the margin. 

 Under parts whitish, with dark bars on the flanks. The 



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