CUCKOO. 173 



Meadow Pipit, and Reed Warbler perhaps by preference. 

 Less frequently a domed nest like the Wren's, or a nest 

 in a covered site like the Pied Wagtail's or the Redstart's 

 is selected. Usually the nest belonging to an insectivorous 

 species is chosen ; more rarely that of a Finch, a Bunting, 

 or even a Red-backed Shrike. Exceptionally the eggs 

 of the Cuckoo have been found in such very ill-adapted 

 nests as those of the Jay, the Magpie, and the Little 

 Grebe. There can be little doubt that the Cuckoo will 

 drop her egg into the nest of a great variety of birds, 

 although few of them are ever discovered by naturalists. 

 RANGE OF EGG COLOURATION AND MEASUREMENT : 

 The number of eggs laid on an average by each 

 individual female Cuckoo every season is difficult to 

 discover, but probably the estimate of from five to eight 

 is tolerably correct. Two and even three eggs have 

 been found in one nest, but whether the produce of the 

 same female is somewhat problematical. They vary 

 considerably in colour, and as they frequently, but by 

 no means generally, resemble those in the selected nest 

 in this respect, it has been maintained that the female 

 Cuckoo possesses the power of laying eggs similar in tint 

 to those of the chosen foster-parent at will. The eggs 

 of the Cuckoo, however, appear to present several well- 

 marked types, like the eggs of the Tree Pipit, the Red- 

 backed Shrike, and many other birds, each type probably 

 not subject to a very great amount of variation, although 

 certainly to some. The Cuckoos laying eggs of each of 

 these certain types, select as far as possible the nests of 

 species containing eggs most similar to them in colour ; 

 whilst the young Cuckoos, with an inherited tendency to 

 produce eggs like their parent, must have a strong 

 inclination to seek the nest of those birds that served as 

 their own foster-parents when the time comes for them 

 to lay eggs of their own, and to provide for their ultimate 



