AVIAN GENUS CHRYSOCOCCYX 99 



of these cuckoos do feed fledglings of their own kind. Out of the 33 

 instances on which I have compiled data, the sex of the food-bearing 

 bird was stated in only 13 cases, and in 12 of these it was male. In 

 only a single instance, of which I was unfortunately unaware at the 

 time (Millar 1926, p. 28) was the food-bearmg bird stated to be a 

 female, and this account was written in so loose and anecdotal a 

 manner that it seemed too unfirm a basis for a unique unit of informa- 

 tion. In all the other cases, either the sex of the food-brmgmg bird 

 was not mentioned, or some element of uncertainty was expressed. 

 Maclaren (1952, pp. 684-685; 1953, p. 167) reported a case that may 

 have involved a female as well as a male food-bringing didric cuckoo. 



Once a male and what I considered to be a female each caught 

 caterpillars and retiu-ned to perches two feet apart foiu" times 

 running, at intervals of 40 to 45 sees., without taking apparent 

 notice of one another. 



There were at least five birds concerned in this orgy — the 

 definite male, the presumed female . . . and thi-ee others which 

 may have been female or immature; these spent much time 

 chasing one another. Tmce in half-hour stretches one of these 

 three fed another female or immature bird, to apparent repletion. 

 Each time the catcher retiu-ned to the neighbourhood of the 

 other stationary bird it displayed, with drooping wings, cocked 

 tail and extended neck. As it hopped nearer it gave four or five 

 bobs, and uttered three or foiu" low calls of the type associated 

 with the species. The caterpillar was taken without any display 

 by the recipient .... 



That the food bearers in this case always displayed when offering 

 the caterpillar suggests (but does not prove) that they were adult 

 males. Similarly, in a case concerning C. klaas, Baird (1945, pp. 

 565-566) reported seeing an adult male catching dysdercid bugs 

 and feeding them to two young cuckoos. He also stated that a week 

 or so earlier a friend had seen a "pair of Klaas's Cuckoo fly back- 

 wards and forwards . . . with Dysdercid bugs .... It can only 

 now be presumed that the parent birds must at this time have been 

 feeding the young while still nesthngs . . . ." There is no proof, 

 however, that the "pair" of klaas cuckoos actually were a pair or 

 that both (or either) had been bringing the bugs to any young cuckoos, 

 in or out of the nest. The fact that Baird saw the adult male feeding 

 two fledglings may suggest that it was acting in a parental way, 

 but it might also be that it was indulging in courtship feeding with 

 two hens simultaneously. 



Another fact that caused me to question the basic nature of fledghng- 

 feeding behavior is that in the cases most completely reported — the 

 relatively few with corroborative details — the feeding male presented 

 each morsel of food, usuaUy a caterpiUar, with a definite courtshiphke 



