cuckow. 395 



hatched the eggs or young, if such there were, of its foster- 

 parent disappeared from the nest, of which the interloper 

 remained the sole tenant, hut the way in which they were 

 got rid of was wholly unsuspected until ascertained hy 

 Jenner. Some people believed with Lottinger that the 

 parent Cuckow was the author of their destruction,* others 

 supposed that they were smothered by the disproportionate 

 size of their fellow-nestling and their corpses cast out hy their 

 own parents. By a succession of experiments, the particulars 

 of which it is here impossible to give, Jenner learnt that the 

 young Cuckow, alone and unaided, was the agent, and it was 

 in June 1787 that he ascertained this fact. On the 18th of 

 that month he examined a Hedge- Sparrow's nest, which 

 then contained a Cuckow' s egg and three eggs of its owner. 

 Inspecting it the next day he found therein a young Cuckow 

 and a young Hedge- Sparrow, and as it was so placed that 

 he could distinctly observe what went on in it, he, to his 

 astonishment, saw the former, though so lately hatched, in 

 the act of turning out its companion : — 



" The mode of accomplishing this was very curious. The 

 little animal with the assistance of its rump and wings, 

 contrived to get the bird upon its back, and making a lodge- 

 ment for the burden by elevating its elbows, clambered back- 

 ward with it up the side of the nest till it reached the top, 

 where resting for a moment, it threw off its load with a jerk, 

 and quite disengaged it from the nest. It remained in this 

 situation a short time, feeling about with the extremities of 

 its wings, as if to be convinced whether the business was 

 properly executed, and then dropped into the nest again. 

 With these (the extremities of its wings) I have often seen 

 it examine, as it were, an egg and nestling before it began 

 its operations ; and the nice sensibility which these parts 

 appeared to possess seemed sufficiently to compensate the 

 want of sight, which as yet it was destitute of. I afterwards 

 put in an egg, and this, by a similar process, was conveyed 

 to the edge of the nest, and thrown out. These experiments 



* Yet in 17S2 Lottinger himself had personal i>roof of the expulsion of an 

 egg from the nest by a young Cuckow (Hist, da Coucou d'Europe, p. 18). 



