102 U.S. NATIONAL MUSEUM BULLETIN 2 65. 



In his study of display behavior of birds, Armstrong (1942, pp. 

 29-35) considered courtship feeding a "recrudescence of an infantile 

 mode of behaviour . . . ," and noted that it is usually accompanied 

 by a considerable amount of psychobiological excitation and appears 

 to be present mainly in species in which the pairing union is strong 

 and prolonged. The fact that this situation is probably not true of 

 the glossy cuckoos led me (1949a, p. 185) to suggest that when this 

 ancient, vestigial courtship activity appears in these birds it may be 

 lavished on fledglings as well as on prospective adult mates. It still 

 seems possible that the catering cuckoos (males in most instances) 

 may not always be aware of the maturity or immaturity of the indi- 

 viduals they feed. However, it does seem that they deliberately offer 

 food to birds too young to be mistaken for adults, so that, in part at 

 least, they are fledgling feeders as weU as courtship feeders. 



Moreau (1944) considered fledgling feeding an indication that the 

 whole picture of brood-parasitism was not as "advanced" or "per- 

 fected" in the glossy cuckoos as in some other genera of the family. 

 However, there are a good number of observations on the Australian 

 pallid cuckoo, Cuculus pallidus, that show it to indulge in fledgling 

 feeding at least as often, it not more frequently, than do the species of 

 Chrysococcyx. That such a habit is found in a member of the genus 

 Cuculus is more surprising, since this behavior has not been noted in 

 the European Cuculus canorus, the best observed of all parasitic 

 cuckoos. It shows that the extremely high development of speciali- 

 zation for brood parasitism in C canorus is a specific and not a generic 

 matter. In his summarizing book on all that he knew of Indian and 

 European cuckoos. Baker (1942, p. 177) concluded that there was no 

 evidence to support the thought that any of these parasites ever 

 exhibit any interest in their eggs or young. While this suggests that 

 the Asiatic forms of Cuculus (canorus, optatus, micropterus, etc.) and 

 of Hierococcyx, Cacomantis, Penthoceryx, Clamator, Surniculus, and 

 Chrysococcyx had not been found to feed fledglings, it certainly is not 

 true for the koel, Eudynamis scolopacea, which has been reported as 

 doing so not infrequently. The absence of Asiatic records of fledgling 

 feeding by Cacomantis is offset by Australian observations of this 

 behavior in the fan-tailed cuckoo, Cacomantis flabelliformis. Another 

 Australian cuckoo known to exhibit this trait is the large channel-bill, 

 Scythrops novaehollandiae}'^ 



Fledgling, and even nestling, feeding occurs from time to time in a 

 number of species of cuckoos belonging to at least five genera. The 

 significant difference between Chrysococcyx and Cuculus in this regard 



" For pertinent references on Australian instances, other than Chrysococcyx, 

 see: Chisholm 1940, 1950; Friedmann 1949b; Hanscombe 1915; Howe 1905; 

 Jackson 1949; Learmonth 1949; Robinson 1950; White 1950. 



