284 Cuculidcv. 



the nests of some one species of birds, which are fit to act the part 

 of foster-parents: so, in order that these latter may the less readily 

 observe the strange egg, it is found to be of similar colouring to 

 their own ; and for the same reasons it is also so disproportionably 

 small. Then every pair of Cuckoos seeks its old district, or that 

 spot where it breeds, just as all other birds do.* Here it generally 

 finds those species of insectivorous birds which it requires for its 

 peculiar circumstances : but assuredly they are not always in the 

 necessary number, or perhaps they may for some cause be breed- 

 ing earlier or later than its six to eight weeks' time for layingt 

 lasts : it will therefore be unable to find for each of its eggs a fitting 

 nest of that species to which it was prepared to entrust it, and to 

 which it was accustomed ; and so it finds itself obliged to intro- 

 duce one and another egg into the nests of some other species, if 

 haply by good chance it can do so.J Thus then it comes to pass 

 that there are, and from the nature of the circumstances there 

 must be, proportionably many exceptions to the rule. Thus too 

 it comes to pass that by far the greater number of Cuckoos' eggs 

 bear the type of the eggs of the ' White-throat' (Sylvia cinerea), and 

 of the ' Pied Wagtail' (Motacilla Yarrelli) t thQ most common foster- 

 parents of the young Cuckoo ; and perhaps, in some localities, of 

 the 'Meadow Pipit' (Anthus pratensis), the 'Hedge Accentor' 

 (Accentor modularis), and of the ' Reed Wren ' (Sylvia arundi- 



Blyth's edition of White's * Selborne,' p. 78. 



f * Legezeit ' is the concise German word, for which we have no English 

 equivalent. 



The Cuckoo, however, alone of British birds, is generally supposed to 

 have the faculty of retaining her egg in the ovarium, after it is arrived at 

 maturity, for a limited period of time. (Montagu's ' Ornith. Diet.,' Intro- 

 duction to vol. i., p. 8. Jesse's ' Gleanings in Nat. Hist.,' p. 125.) If this 

 be correct, it will account for the egg laid by the Cuckoo as it fell to the 

 ground after it was shot, recorded by Mr. S. S. Allen (Ibis, vol. iv., p. 358), 

 and by my friend Mr. Chambers (Ib is, vol. v., p. 475). See also M. Yail- 

 lant's account of the African Cuckoo shot by himself and his faithful 

 attendant, the Hottentot Klaas, and the frequent occurrence of the egg laid 

 by the Cuckoo as she fell wounded from the tree. (Rennie's 4 Architecture 

 of Birds/ p. 378.) 



The Pied Wagtail, the Meadow Pipit, and the Hedge Warbler, are 

 perhaps most frequently chosen as the foster-parents in this country. 



