354 CUCULIFORMES chap. 



produced in a season ■ — possibly five or six — or whether the 

 same hen ever places two or more in one nest. It is now certain 

 that the egg is laid on the ground and conveyed to the chosen 

 nursery in the bill, an occurrence said to have been actually 

 witnessed by Adolf Miiller, a forester in Darmstadt. 



Closely connected with the above parasitic habit is the question 

 of the colour of the egg. Eed or blue specimens have undoubtedly 

 been found in Germany and elsewhere, as well as the typical 

 brown or greyish varieties ; but they do not always assimilate 

 to those of the foster-parent, albeit to the eggs of Pipits, Wag- 

 tails, and so forth, that of a Cuckoo is often exactly similar. The 

 theories advanced to account for this are by no means conclusive, 

 though hereditary habit may afford a clue ; we may, however, be 

 sure that the hen cannot determine the colour of her egg. 



With us the most usual foster-parents are the Meadow-Pipit, 

 Pied Wagtail, Eeed Warbler, Hedge-Sparrow and Robin, perhaps in 

 the above order. They seldom, if ever, seem to resent the intru- 

 sion, or to notice their consequent losses. The careful observations 

 of Jenner, Hancock, and Mrs. Blackburn shew that the young 

 Cuckoo, when some thirty hours old, begins unaided to remove from 

 the nest the rightful progeny or unhatched eggs by means of its broad 

 back, which has a central depression for the first twelve days ; but 

 after this hollow is filled up the desire is said to cease. It pushes 

 below a nestling with its wings, and raises it with much exertion 

 to the edge of the nest, finally ejecting it by a supreme effort. 



The probable reason why the Cuckoo's egg often hatches first is 

 the hen's habit of selecting nests with only one or two fresh eggs. 

 Subsequently she neglects her offspring entirely. It is stated 

 that the males, who alone utter the well-known notes, decidedly 

 outnumber the females, and that no strict pairing takes place ; 

 while in the courting season a curious bubbling sound, attributed 

 to the hen, may be heard as two or three individuals chase each 

 other along the hedgerows. Wooded districts and bare hill-moors 

 are equally frequented, trees being constantly used as perches. 

 The quick, straight flight is varied by twists and swoops ; the 

 food consists of insects and their larvae, the stomach often becom- 

 ing lined with hairs of caterpillars. Our Cuckoo does not eat eggs, 

 but various foreign species add to their diet seeds and other fruits, 

 land-molluscs, worms, frogs, lizards, small snakes, birds, and mice. 

 Chalcococcyx lucidus bruises its food before swallowing it. 



