CUCKOO. 383 



extreme voracity of tlie young bird is an additional reason why the care 

 of the five nestlings should be entrusted to as many pairs of birds. What- 

 ever may have been the cause of this apparently unnatural habit, the 

 result has been remarkably successful in the case of the Common Cuckoo, 

 which must be regarded as a common bird with a very wide distribution, 

 and scattered over almost every variety of country within its range. 



In its choice of a foster-parent for its ofispring it exercises -more 

 discrimination than might be supposed, from the long lists which have 

 been published of birds in whose nests its egg has been found. An 

 insectivorous bird is generally chosen. The Pipits and the Wagtails are 

 perhaps the greatest favourites ; and in our islands Cuckoos'" eggs are 

 most often found in the nests of the Meadow-Pipit and Pied Wagtail. 

 In gardens the Hedge-Sparrow is most frequently entrusted with the 

 charge, and in the fens the Reed-Warbler. In some districts Redstarts 

 have the preference, and in others, curiously enough, the Common Wren. 

 There is probably no insectivorous bird which breeds in the districts where 

 the Cuckoo spends the summer in whose nest its eggs are not occasionally 

 deposited, though preference is given to such as build open nests. Some- 

 times the Cuckoo is unable to find the nest of a suitable bird, and is 

 obliged to deposit its egg in the nest of a granivorous bird, such as the 

 various species of Finches, Buntings, &c. ; and occasionally Cuckoos' eggs 

 have been found in the nests of such totally unsuitable birds as Magpies, 

 Jays, Shrikes, Pigeons, and even the Little Grebe. The Cuckoo's egg is 

 remarkably small in proportion to the size of the bird, and it is generally 

 placed amongst eggs which are smaller than itself ; so that the young 

 Cuckoo is usually much larger than its foster-brothers or sisters, and 

 monopolizes the attention of the parents to the exclusion of the other 

 inhabitants of the nest, who die or are eventually expelled by the young 

 Cuckoo. It has been said, on what appears to be incontestable evidence, 

 that the young Cuckoo soon after it is hatched ejects the young or eggs 

 from the nest by hoisting them on its back ; but one feels inclined to class 

 these narratives with the equally well-authenticated stories of ghosts and 

 other apparitions which abound. 



The eggs of the Cuckoo are subject to great variation of colour, and 

 they very frequently resemble closely the eggs amongst which they have 

 been placed, so much so that Cuckoos' eggs are often supposed to be 

 double-yolked eggs of the same species. This fact has given rise to the 

 extravagant theory that the Cuckoo possesses the power of determining 

 the colour of her eggs, so as to make them resemble the other eggs in the 

 nest. The explanation probably is that the eggs of each individual Cuckoo 

 vary very slightly. A Cuckoo which lays blue eggs always lays blue eggs, 

 and its descendants will continue to lay blue eggs; it was probably 

 hatched in a nest containing blue eggs, and will, to the best of its ability. 



