Reason of Zygodactyle Feet, ii 



Lord Lilford says : " I once and only once met with 

 a cuckoo's egg in a spotted fly-catcher's nest." " 



These facts have forced naturahsts to conclude that 

 the cuckoo does not lay the egg in the nest at all, but 

 lays it on the ground and carries it in its beak, and so 

 deposits it in the nest chosen for it. This has now 

 been observed and verified by so many naturalists 

 that it cannot be doubted ; and this fact disposes of 

 the fine theory of some distinguished speculators that 

 the zygodactyle feet — that is, feet with two toes 

 behind and two toes in front, as in the case of parrot 

 and wood-pecker — admirably enabled it to lift and 

 carry its eggs m its claws. The reason for the zygo- 

 dactyle feet must therefore be sought elsewhere. 



Looking at Mrs. Blackburn's drawing, it has sug- 

 gested itself to me that here we may have a reason 

 for the zygodactyle feet. A bird with but one smaller 

 shorter toe behind clearly could scarcely so fix its feet 

 beneath as to retain position leaning against the side 

 of the nest with its posteriors : it would slip away. 

 But with the two hind toes with claws well fixed the 

 thing would I think be possible. In the case of the 

 wood-peckers, which for the same reason need to fix 

 themselves in trees, the two hind toes would do much 

 to keep the bird from slipping down through the front 

 toes giving way. There is no such reason I have 

 ever heard of for such a formation in the habits of the 

 cuckoo ; and any hint to account for their presence 

 may be suggestive, and lead others to bring their 

 minds to bear upon it. Any way, I have as yet 

 heard of no other necessity in the life-economy of the 

 bird or adequate explanation of it ; and I shall be 



* Birds of Northamptonshire, i, p. 79. 



