126 Transactions. — Zoology. 



birds in those nests to have less competition for food, would 

 be transmitted as an advantage, while the young Cowbirds 

 which had large families to compete against would have less 

 chance of obtaining sustenance, and would ultimately become 

 extinct(38^). Although writers on the American, ^Australian, 

 and Indian Cuckoos do not report a thieving character thereof, 

 Buller, Potts, and nearly all the writers on the New Zea- 

 land bird make the general statement that it devours the 

 eggs of other birds ; but no specific instance is given. Mr. 

 Potts gives it as his opinion that many of the eggs of the Blue 

 Crow {Gla7icopis cinerea) are destroyed by the Cuckoo, but he 

 brings forward no proof of this(39). Personally, I think that 

 ]f this theory of universal egg -robbing were true it would 

 soon bring about the robbers' extinction, by the nests of all 

 birds which contained an egg of the marauder being deserted, 

 or the egg promptly thrown out by the builder. The " pro- 

 tective resemblance " to a Hawk is, to my mind, acquired 

 partly for the bird's own protection, as it seems to be a poor 

 fighter, but also for the purpose of frightening small birds 

 away from their nests, so that it can quickly seize the oppor- 

 tunity of safely depositing its egg in a comfortable borne. 

 The sudden appearance of a large savage-looking bird would 

 make any little Tomtit fly from its nest, and the marauder in 

 this way could utilise her resemblance for the perpetuation of 

 her species. 



Professor Newton says, " So far as I can find there is 

 nothing to show that any instance has been known of the 

 Cuckoo stealing an egg, and the whole theory of egg-robbing 

 seems to have arisen from the numberless instances of 

 Cuckoos having been found with eggs in their mouths, tbroats, 

 or stomachs. When these instances are carefully investigated 

 the egg invariably proves to belong to the Cuckoo itself. 

 Cuckoos, too, have been not infrequently shot as they were 

 carrying a Cuckoo's egg, presumably their own, in their bill, 

 and this has probably given rise to the vulgar but seemingly 

 groundless belief that they suck the eggs of other kinds of 

 birds "(40). 



When we carefully investigate the habits of the Kohoperoa 

 we do find that instances have been known of his eating 

 an egg, but more often young birds, though this is a habit by 

 no means universal, and no more common tlian in many 

 other birds which are not credited with these villainous pro- 

 clivities. The Native Kingfisher {Halcyon yagans), which 

 preys on mice and small fish, &c., has been seen to attack 

 and devour a fully adult Fantail {Rhipidura flabcllifera), and 

 fiy off with several inches of tail-feathers protruding from its 

 beak(40a) ; and the Thrush {Turnagra crassirostris) has 

 similar propensities(3o). The fact that our bird is so per- 



