lH BOOK Of MIGRATORY BIRDS iQl 



of circumstances by which it would be developed might 

 lead to something which would unlock the mystery. 



Birds possessing this parasitical economy are exceed- 

 ingly few in numbers. 



It arrives in April, and immediately proclaims the fact 

 to its mate. This is continued unremittingly until the 

 breeding season has passed, the note gradually becoming 

 hoarser and more indistinct as the season advances, and 

 ultimately before their departure they are entirely mute. 



July usually sees the last of them the first migrants to 

 leave our shores. The period of remaining in the British 

 Isles appears to be limited to the time necessary for a 

 selection of nest and laying the quota of eggs. 



The bird is very generally distributed, and is found in 

 districts of every character. In this respect it differs from 

 the nightingale, which is very seldom heard in the mining 

 districts of South Wales, although across the Bristol 

 Channel, on the coasts of Somerset and Devon, it occurs 

 frequently and regularly. In choosing its nest, it goes 

 invariably for that of insectivorous birds, like itself, and 

 caterpillars form its staple food, hence its partiality for 

 lands of high pasture and moorland. 



The plumage of the head, neck, breast, and upper 

 partsl is of a deep bluish-grey. The whole of the belly 

 and remaining under parts, and auxiliary feathers 

 white, with pretty distinct black bars. The quills are 

 blackish - grey, the inner webs have white bars. Tail 

 of a darker tint, blackish at the end. Feet, dark 

 yellow. The sexes are much alike in coloration ; so 

 unlike the sea birds. But the most complete account 

 of what was anciently known and believed of these 

 singular birds is given by Pliny an authority which most 

 naturalists will accept. He says: "They alwaies lay in 

 other bird's nests, and most of all in the stockdove's, 

 commonly one egge and no more (which no other bird 

 doth besides), and seldom twain. The reason why they 

 would have other birds to sit upon their eggs and hatch 

 them, is because they know how all birds hate them, for 



