3i8 THE WONDER OF LIFE 



In most cases the mother-cuckoo lays her egg on the 

 ground, then takes it in her bill, and then puts it as quickly 

 as possible in a suitable nest. Baldamus and others have 

 vouched for the fact that the bird sometimes lays her egg 

 in the nest while sitting on the nest-wall. This is said 

 to occur especially in the case of open and not too fragile 

 nests. According to Baldamus the cuckoo lays five or 

 six eggs at intervals of six or seven days ; some observers 

 state the intervals as two or three days. There is probably 

 a good deal of variability in this regard, just as in the 

 colour of the eggs. 



The entire progeny of the cuckoo-nurse is destroyed. 

 According to Jenner, Blackwall, Durham Weir and many 

 others, the young cuckoo gets the egg or offspring of the 

 foster-mother on to its broad depressed back, and climbing 

 on the side of the nest ejects the rightful tenant. This 

 effective dog-in-the-mangerish behaviour is probably, 

 Herrick thinks, ' a reflex response to a contact stimulus 

 of a disagreeable kind '. Blackwall made the significant 

 remark : ' I observed that this bird, though so young, 

 threw itself backwards with considerable force when any- 

 thing touched it unexpectedly '. It has a convulsive hitch- 

 ing movement of legs and wings and body, which appears 

 to be exhausting. The response dies away when the bird is 

 ten to fourteen days old, after which anything is tolerated 

 in the nest. 



According to Baldamus and some other Continental 

 observers, the mother-cuckoo, who may be accompanied 

 by a male, occasionally removes the eggs of the nurse — 

 which is the more remarkable since the cuckoo is not an 

 egg-eater, but feeds mainly on hairy caterpillars and other 

 insects. Baldamus also states that in nests which the 



