AVIAN GENIJS CHRYSOCOCCYX 95 



period during which this bird could be said to have remained 

 with its fosterer was 28 days and the minimum 18. . . . 



The same observer found the period of postfledging feeding of 

 caprius by masked weavers, Ploceus velatus, lasted from 22 to 26 

 days; and by Cape sparrows, Passer melanurus, from 17 to 37 

 days! Because of their unique richness in detail, further quotation 

 from Reed's notes seem desirable. 



On December 23, 1954, a juvenile didric was uttering the 

 hunger call and was attended by Cape sparrows. This bird I 

 observed almost daily and, on December 31, it was joined by 

 another juvenile didric also waited upon by Cape sparrows. 

 Subsequent to that date I observed only one didric in company 

 mth Cape sparrows in this area and the last time I saw this bird 

 was January 29, 1955. During this period, under close observa- 

 tion for nearly a month, I always found this didric within a radius 

 of approximately 50 yards of the tree where it was first seen. 

 Because there were two didrics together at one time I cannot say 

 which of the two remained in the area to the last and I must 

 therefore state that the maximum post nestling period was 37 

 days but the minimum was at least 29. 



I have one more postnestling record for a didric reared by 

 Cape sparrows and that is of a chick which was fidly fledged in a 

 Cape sparrow nest at 6:30 a.m. on March 11, 1955 and which 

 had left the nest by 6:30 p.m. on the same day. This chick re- 

 mained in this vicinity — I always found it mthin a radius of 

 approximately 30 yards of a central point — until March 28th, 

 giving a period of 17 days .... 



A parasitic bird, reared by any of a number of possible host species, 

 is aided by a fairly broad tolerance of food items and even of feeding 

 methods. Thus, the method of feeding the fledgling didric cuckoo 

 by red bishops is quite different from that employed by either the 

 Cape or masked weaver or by the Cape sparrow. The red bishop 

 invariably feeds the young with regurgitations from its crop. Reed 

 informed me that on several occasions he counted more than 40 of 

 these short, jerky regurgitations in a single continuous feeding. 

 On the other hand, the masked and the Cape weavers bring a sizable 

 grub or other insect, and each feeding operation consists of a single 

 offering. Whereas these birds feed their own young and their parasitic 

 young on insects exclusively, the red bishop uses soft seeds extensively. 

 The droppings of young didrics reared by red bishops often are full 

 of small grass seeds. 



While the cuckoo young in general may thus experience a more 

 varied diet than do the young of any one of its fosterers, there are, 

 of course, obvious limits to what it can take in its stride. That all 

 the glossy cuckoos are parasitic on small passerine species in itself 

 limits the range or variety of their nutriment. 



