II 



BIKDS THAT TAKE THE WKONG TUENING 

 THE CRIMINAL CUCKOO 



I 



MAY I be permitted to add to your answer to the in- 

 quiry in your last number about the power of the cuckoo 

 to alter the coloration of its eggs ? The cuckoo does many 

 wonderful things from its birth to its death, but it has 

 no power to colour its eggs according to its own wish, and 

 once the egg is laid the colour is fixed. The average tone 

 is that of something between the skylark and the wagtail, 

 but it also lays eggs as blue as a hedge-sparrow, red as a 

 robin, and even quite white. The cuckoo lays from five 

 to eight eggs at intervals of about four days. My theory 

 is that the cuckoo resembles the guillemot, which lays 

 different coloured eggs, and that one cuckoo always lays 

 the same coloured egg, be it blue, brown, white, or red, 

 or any variety. It has laid its egg in the nests of some 

 forty birds which breed in England, and has no fixed rule 

 i.e., the blue egg is found in many nests where the egg 

 of the foster-parent is very different. A young cuckoo 

 is by nature entirely selfish, for in a few hours after birth 

 it begins to eject (aided by a cavity in its back, which fills 

 up in about ten days) the offspring of its foster-mother 

 from the nest, and should there be another cuckoo in the 

 nest, the weaker is heaved over the side. It is a great 

 pity that Miss Hilda Terras, in her charming book to 

 which you refer, did not give us photographs of the acts 

 of ejection. We have a lot of cuckoos round here. I have 



83 



