478 THE CUCKOO 



got pushed up to the upper edge of his side, he would begin to fidget 

 more and more, and this would cause it to move round, and so to 

 increase the irritation by touching and pressing against other parts. 

 When all the bird's efforts to get away from the object had only made 

 matters worse, he would cease wriggling, and squat down lower and 

 lower in the bottom of the nest, and the egg, forced up, would finally 

 roll right into the cavity in his back the most irritable part of all. 

 Whenever this occurred, a sudden change that was like a fit would 

 seize the bird ; he would stiffen, rise in the nest, his flabby muscles 

 made rigid, and stand erect, his back in a horizontal position, the 

 head hanging down, the little naked wings held up over the back," 

 and the work of ejection would recommence. When the egg had 

 been finally ejected, the rapid growth of the two nestlings made the 

 position of the cuckoo more and more intolerable. A fresh series of 

 struggles began, but success did not come till the little curved beak of 

 the robin came accidentally into contact with the centre of the cuckoo's 

 hollow back. Instantly the latter pressed down into the nest "shrink- 

 ing away as if hot needles had pricked him, as far as possible from the 

 side where the robin was lying against him, and this movement of 

 course brought the robin more and more over him, until he was 

 thrown right upon the cuckoo's back. Instantly the rigid fit came on, 

 and up rose the cuckoo, as if the robin weighed no more than a 

 feather on him ; and away backward he went, right up the nest, with- 

 out a pause, and standing actually on the rim, jerked his body, 

 causing the robin to fall oflf clean away from the nest." 



Mr. Hudson's account makes it appear that the young cuckoo's 

 extreme sensitiveness to pressure upon its sides and upper parts is 

 what causes it to perform the act of ejection. Its first desire is to 

 remove its sides from the source of irritation ; it wriggles with 

 discomfort, and finally seeks escape by flattening itself down in the 

 bottom of the nest. The effect, however, of this movement, is to 

 throw the egg or nestling onto or across its back, and into contact 

 with the most sensitive spot of all, the hollow in its back. It shrinks 



