62 Wizard Cuckoos 



due to the same process of gradual assimilation, 

 proceeding with less interruption, since the eggs 

 of the cuckoo's usual hosts are much more closely 

 alike in size than in colour. It is noticeable that 

 cuckoos' eggs found in wren's nests one of the 

 less common attachments seem usually to be much 

 smaller than others, though by no means so small 

 as the wren's. This appears to be another illustra- 

 tion of the conflict of the fixed hereditary tendency 

 of the female cuckoo with the varied influences 

 of the males. Cuckoos' eggs offer evidence of 

 degeneration from an original type, not only in 

 their disproportionate smallness, but in their pecu- 

 liarly indecisive and, as it were, atrophied markings. 

 Compared with the eggs of almost all other British 

 birds, they are stamped with the vagueness of a 

 compromise. Besides their usual faded mottlings, 

 they also show, as a rule, faint dots and dashes of a 

 darker and more superficial pigment, which appear 

 to be the last remaining traces of a more positive 

 scheme of colour. As the May nests multiply in 

 the garden and meadows, the appearance of a 

 cuckoo's egg in a hedge-sparrow's nest, or some 

 less frequent nursery, presents a perpetual and 

 suggestive exception to ordinary rules. It is deeply 

 interesting to come upon the one greenish egg lying 

 among the four or five others, to reflect upon the 

 strange career of the nestling to be born from it in 

 a few days more, and to endeavour, in the light of 

 the rebellious contrast of the cuckoo's habits, to 

 understand more clearly the ordered interests and 

 relationships of all our birds. 



