AVIAN GENUS CHRYSOCOCCYX 93 



containing 5 similar eggs and when I visited it on February 5, 1956 it 

 contained two red bishop chicks, one approximately 24 hours old and 

 the other freshly hatched together with one didric chick approxi- 

 mately one to two days old. When this nest was again visited on 

 February 11 it contained only a didric cuckoo chick. . . . 



In the case of the European cuckoo, Cuculns canorus, the habit of 

 the very young nestling of evicting its nest-mates from the nest is 

 always described as facilitated by the hollow, somewhat concave 

 shape of its back, affording a place on which to balance the egg or 

 young to be evicted. No such hollowing has been described for any 

 of the glossy cuckoos, but the didric, C. caprius, does have a decidedly 

 flattened back which is somewhat hoUowed by the action of the bird, 

 which in the process of evicting usually raises its featherless wings 

 above the plane of its back to help balance the object it is about to 

 evict. Otherwise it would be difficult to see how the young cuckoo 

 could carry an egg almost its own size up a perpendicular nest wall 

 several times it own length. 



Mellor (1917, p. 18) noted of C. lasalis that a newly hatched chick 

 had an "abnormal spike" at the alula and that its claws were curved 

 and exceedingly sharp. This has not been noted in other species of 

 glossy cuckoos. 



The length of time after fledging during which the fosterer con- 

 tinues to feed the young parasite is of interest insofar as it interferes 

 Avith the host's renesting and rearing a brood of its own. The survival 

 of the population of the host species is clearly of importance to the 

 parasite if the latter is to continue to have an adequate supply of 

 host nests. The data available on four species of glossy cuckoos sug- 

 gest that each instance of parasitism may have a prolonged effect, 

 sufficiently lengthy to affect adversely the possible recuperation of 

 the host species. Thus, in the south Australian basalis Kikkawa and 

 Dwyer (1962, p. 171) found that the fledgling still gapes for food 

 from passing birds for as long as six weeks after lea"\dng the nest, a 

 much longer period than the usual postfledging feeding period of the 

 host involved in this observation (Acanthiza chrysorrhoa) . It was not 

 stated, however, that the Acanthiza actually gave much attention to 

 the young cuckoo for this long time. 



In the African Haas, J. Paludan (in litt.) wrote me that at Leopold- 

 ville, Congo, he watched a pair of Cyanomitra verticalis that continued 

 to feed a young Klaas's cuckoo which they had reared for at least 10 

 bays after fledging. A still-longer period was noted by Ryves (1959, 

 p. 175) who watched a pair of Nectarinia kilimensis feeding a fledgling 

 cupreus for 26 days after it left their nest. 



The data on the didric, C. caprius, reared by a Cape weaver studied 

 dy Skead (1947), who found it to be fed by its host for about a fort- 



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