103 [Vol. xlii. 



bird's eo-g is visible in the bill, and her throat is relaxed and 

 the feathers lie flat. Again, we should consider what are 

 the Cuckoo's motions in the nest, so far as can be judged by 

 the films. She gets into the nest as speedily as possible, and 

 at once bends down her head under her body. My own 

 idea is that she now regurgitates and deposits her own egg- 

 in the nest, takes up one of the foster-parent's eggs in her 

 bill, and flies off. 



Mr. Charles Inglis and I myself have both been fortunate 

 enough to see Clamator jacobinus place her own egg in the 

 nest of Turdoides terricolor. In neither case did the bird get 

 into the nest, but leant right over it, and when she flew off 

 in each case the eo-p- of the fosterer was visible in the 

 Cuckoo's bill, though in neither case could we detect any 

 sign of the egg in the Cuckoo's bill when she came up. In 

 the case in which I saw the operation performed, the Cuckoo 

 dropped down on the grass just a few yards in front of me 

 and with her back towards me^ put her head right down, 

 heaved, and then flew up to the Babbler's nest, whence she 

 took an egg and returned to the ground, and again back at 

 once to the nest, having apparently exchanged the Babbler^s 

 for her own egg, for when I went up to the nest, there was 

 the Cuckoo's egg on the top of three of the Babbler's and 

 the fourth was lying on the ground broken — smashed, I think, 

 by the bird, startled by suddenly catching sight of me. 

 This idea of regurgitating the egg struck me when I saw the 

 part of Mr. Chance's film showing the parents feeding their 

 young. In this the male regurgitates twice and brings up 

 insects which he passes over to the female, yet the swelling 

 in the gullet is not noticeable, but the head and shoulder 

 action of the male is exactly like that of the female Cuckoo 

 on the nest. To this question, as to how the female Cuckoo 

 deposits her egg in another bird's nest, I would, therefore, 

 venture to suggest that she does so with her bill, carrying 

 the egg in her gullet until such time as she thinks appro- 

 priate for the job, when she flies down to the nest, regurgi- 

 tates, drops the egg in^ and flies off, generally taking one of 

 the fosterer's in exchange. 



