VI HABITS OF THE CUCKOO 259 



its own eggs, as conversely the American cuckoo now only 



occasionally lays its eggs in other nests. Who can prove 



that reflection did not underlie this difference of action, 



determining it according to the different conditions ? For the 



cuckoo certainly shows reflection in its choice of nests in 



which to lay its eggs, and in many other actions. Ihit 



whether our cuckoo acts at the present day from pure instinct 



or still by reflection — even assuming the first — it is, I believe, 



necessary, in order to explain the instinct, to start from the 



supposition that it has arisen by the inheritance of habit 



originally intelligent. The conditions of life of the bird enable 



us to understand easily enough the ultimate causes of the habit. 



The cuckoo lives the life of a vagabond. It wanders about 



restlessly ; in the first place, it remains with us only a few 



months, from April to August; secondly, even in the region 



where it settles here it has no permanent station, it wanders 



now in one direction now in another. This restlessness is 



caused by its insatiable appetite and sexual desires. It is 



ever seeking food and mates. Its food consists principally of 



caterpillars, especially those which, like Gastropacha pini, 



occur only here and there in great abundance. The cuckoo 



must therefore move about in order to satisfy its need of food. 



When it has found a swarm of caterpillars it revels in excess, 



and its sexual requirements are increased. It enjoys on 



account of its loose life the worst of reputations ; the bonds 



of marriage are unknown to it, especially to the lady-cuckoo. 



Brehm says of it, with regard to this : " Any one who doubts 



the intense lustfulness of the cuckoo needs only to visit its 



sleeping-places repeatedly. To-day are heard the voice of the 



female, the soft wooing of the male ; to-morrow only the cry 



of the latter ; the former is then blessing a neighbour or a 



distant mate." ^ Farther on : " Although he meets with no 



reluctance, desire seems to drive him out of his senses. He 



^ Brelira, Illustr. Thierleben, second edition, vol. iv. p. 215. 



