THE WEB OF LIFE 319 



mother- cuckoo cannot readily reach ' the young of the 

 nurse sometimes grow up, but are often suffocated or 

 starved out by the young cuckoo, and are later removed 

 by their own parents for the sake of cleanliness '. There 

 is no doubt at all as to the accuracy of the British 

 observations that the nestling cuckoo evicts the eggs or 

 young of its foster -parent, but it seems that the evicting 

 reaction is not always exhibited or is not always effective. 



After the young cuckoo leaves the nest and has learned 

 to fly, it is still attended by its foster-parents, who continue 

 to offer food to their changeling. It could not be more 

 ' spoiled ' were it their child. Who can tell the inward 

 spirit of the young cuckoo ? But without maintaining 

 that the creature is at all deliberate in its treatment of 

 the rightful tenants of the nest, we cannot agree with 

 those who write as if mental disposition were a negligible 

 quantity. It has its fears, for instance, but how charac- 

 teristically it ' expresses its fear ', as Herrick says, ' in a 

 manner calculated to inspire fear in its common enemies '. 

 Jenner observed that long before it leaves the nest, the 

 irritated bird ' assumes the manner of a bird of prey, looks 

 ferocious, throws itself back, and pecks at anything pre- 

 sented to it with great vehemence, often at the same time 

 making a chuckling more like a young hawk. Sometimes, 

 when disturbed in a small degree, it makes a kind of hissing 

 noise accompanied with a heaving motion of the whole 

 body '. In the American black-billed cuckoo (Coccygus 

 erythrophthalmus), which broods, the young birds give 

 a similar expression to fear, but it occurs earlier and leads 

 to a premature desertion of the nest on the seventh day ! 



Some light on the problem is afforded, as Herrick has 

 shown, by a study of the American cuckoo (Coccygus 



