400 PROCEEDINGS OF THE NATIONAL JMUSEUM vol. loe 



out in competition for the food brought to the nest by the hosts. 

 While the present paper was awaiting publication, MacLeod and 

 Hallack (1956) supplied our first definite observations on this point. 

 They watched a parasitized nest of a Cape flycatcher. The Klaas's 

 cuckoo hatched on November 9, and one of the host's eggs hatched 

 on November 13. On November 14 the J^oung cuckoo evicted the 

 3^oung flycaU'her, At 9 a, m. on that day the cuckoo was noted 

 underneath the young flycatcher, trjang to heave it out of the nest; 

 this attempt was unsuccessful, and was repeated at 9:25, again un- 

 successfully. At 11:42 another attempt succeeded. The young Batis 

 was left dangling by one foot, head down, from the outside of the 

 nest. The adult Batis returned with food, took no notice of its right- 

 ful young, and fed the young parasite. A quarter of a hour later the 

 young flj^catcher fell to the rocks below. 



Chalcites flaviguUtris (Shelley) 



Yellow-throated cuckoo 



This rare cuckoo remains still virtually unobserved. Its range 

 may now be extended a short distance eastward to the Bwamba area, 

 Toro, western Uganda, where the van Somerens (1949, p. 29) collected 

 a breeding female at Ntandi in July and where Ridley, Percy, and 

 Percy (1953, p. 163) obtained another female in full breeding con- 

 dition on September 27 near Hakitengya. The stomacli contents of 

 both birds consisted of hairy cateipillars, plus scale insects in the 

 July bird and beetles in the September one. 



Chalcites caprius (Boddaert) 



Didric cuckoo 



The new information on this cuckoo may be treated under several 

 subdivisions. 



Host Records 



A considerable number of species of birds not listed in my earlier 

 report have now been found to be parasitized by the didric cuckoo, 

 bringing the total of its known hosts to 46 species, or 55 species and 

 subspecies of birds. In addition, our knowledge of some that were 

 included in the 1949 list has been considerably augmented. It be- 

 comes increasingly clear that the Ploceidae are the chief victims of the 

 didric cuckoo; approximately three-fourths of all the nests recorded 

 with eggs or j^oung of the cuckoo belong to birds of this family. 



The Cape wagtail (Motacilla capensis capensis) was included in my 

 (1949a) book on the basis of one, not wholly satisfactory, record. 

 However, an overlooked statement by Nicholson (1897, pp. 142-143) 



