190 BIRD BEHAVIOUR 



than its short legs would lead one to expect.. The 

 Hedge-Sparrow is, however, a well-known victim 

 of the Cuckoo, and is the most often spoken of, 

 since as it is such a familiar bird itself, the alien 

 nestling is most often seen in its easily-found nest 

 in most places^ 



Other well-known Cuckoo-rearers are the Robin, 

 Pied Wagtail, and Reed- Warbler, and many other 

 small birds are patronized, but chiefly the insec- 

 tivorous kinds, though now and then a Finch's nest 

 may be selected. Larger birds are very seldom 

 Cuckoo-fosterers, probably because they can drive 

 off the intruder otherwise we should expect to find 

 the Blackbird, Thrush, and Starling the commonest 

 fosterers, their nests being easy to find and their 

 habits in every way suitable. The Red-backed 

 Shrike, however, in spite of its ferocity, is a not 

 uncommon foster-parent on the Continent, though 

 rarely so in this country. 



In this case, the egg of the Cuckoo seems gener- 

 ally to bear a close resemblance to that of the 

 Shrike, but such resemblance to the egg of the 

 fosterer is not by any means universal. The 

 Cuckoo's egg is indeed very variable, though not 

 nearly so much so as that of the Guillemot ; and its 

 small size relatively to that of its producer is 

 paralleled by the similar smallness of the egg of 

 the Raven above alluded to. The mottled-drab 

 coloration which is the most usual is certainly not 

 very unlike that of Wagtails' and Pipits' eggs, 

 though the resemblance is far closer to that of the 



