424 The Outline of Science 



new evidence, the recent intensive observations and wonderful 

 cinematograph records of Mr. Edgar Chance have placed several 

 points beyond doubt 



The Cuckoo's Procedure 



It seems to be the case that each female cuckoo has its 

 chosen territory of operations and that deliberate choice of nests 

 is made in advance of the date of laying. When the time for 

 laying conies, the selected nest is approached, the cuckoo takes 

 an egg from the nest in its beak, settles on the nest, lays its own 

 egg, and then flies away with the stolen egg, which it either eats 

 or drops at a distance. The whole manreuvre takes but a few 

 seconds and may be carried out despite the frantic efforts of the 

 small and unwilling hosts to drive off the intruder. Sometimes 

 the procedure varies, for no cuckoo could lay in a wren's nest, 

 for instance, and in cases of that kind the egg must be laid out- 

 side and inserted with the beak. The point of principle, however, 

 is that the cuckoo certainly does not fly about carrying an already 

 laid egg and looking for a suitable nest to victimise. 



The Young Cuckoo's Part 



One cuckoo does not normally lay two eggs in the same 

 nest, but different cuckoos may chance to select the same victim 

 if there has been an encroachment of territory. Once the act 

 has been accomplished the foster-parents do the rest until the 

 eggs hatch out; then begins the second part of the Cuckoo's 

 villainy, for the young foundling has in his earliest and com- 

 paratively helpless days the inborn habit of removing the other 

 chicks from the nest by getting his back under them and heaving 

 them overboard. So it happens that the foster-parents are soon 

 left with but one charge, whose voracity keeps them perpetually 

 busy and whose body speedily fills up the nest. Still the poor 

 dupes go on feeding the parasite, even when he is much bigger 

 than they are ; one of Mr. Chance's photographs shows a bloated 



