52 U.S. NATIONAL MUSEUM BULLETIN 2 65 



glossy cuckoos are the paradise flycatcher, Terpsiphone viridis, Avith 

 5 records for C. caprius and 10 for C. Idaas, and the red-breasted sun- 

 bu-d, Nedarinia erythroceria, mth 5 records for C. caprius and 22 for 

 C. klaas. 



The list of hosts common to the two cuckoos includes 2 species of 

 Moiacilla, 1 of Turdiodes and Parisoma, 2 of Cisticola, 1 of Prima, 

 2 of Nedarinia, 1 of Cyanomitra, 1 of Plocepasser, 3 of Passer and of 

 Ploceus, 1 of Malimbus and 2 of Eupledes. The possibility of error in 

 the identification of the cuckoo eggs in some of these instances cannot 

 be rided out, although I have been at some pains to eliminate records 

 that for one reason or another seemed uncertain. The eggs of caprius 

 and klaas ai"e not always distinguishable with certainty. 



The data on Klaas's cuckoo comprise some 210 records of parasitism 

 on 59 species of birds. The three most important groups of fosterers are 

 as follows. Sunbhds (Nectariniidae) 85 records, or 40 percent of the 

 total number, involving 16 species, or 27 percent of all reported hosts; 

 warblers, flycatchers, and thrushes (Muscicapidae) 89 records, or 42.3 

 percent of total number, involving 25 species, or 42.3 percent of all re- 

 ported hosts; weaverbirds (Ploceidae), 27 records, or 12.8 percent of the 

 total number, involving 12 species, or 20.3 percent of all reported hosts. 

 These figures are in sharp contrast to those for the didric, where 81 

 percent of all instances of host choice was of weaverbhds; where only 

 9 percent of the cases was of warblers, flycatchers, or thrushes, and 

 only 4 percent was of sunbirds. 



In descending order of frequency, the main hosts of Klaas's cuckoo 

 are as follows: Chalcomitra senegalensis, 25 records; Nedarinia eryth- 

 roceria, 22; Prinia subflava, 20; Terpsiphone viridis, 10; Cinnyris afor, 

 9; Chalcomitra amethystina, 9; Apalis thoracica, 8; Batis capensis, 8; 

 Alseonax minimus, 8; Ploceus reichenoud, 6; Ploceus intermedius, 5; 

 Cinnyris venustus, 5; and Apalis jiavida, 5. The mere number of records, 

 however, does not give a true picture of the relative frequency of par- 

 asitism of each host species, since these numbers are readily increased 

 as further study is given to any one particular host. At Kampala, 

 Uganda, Alseonax minimus was considered the commonest fosterer 

 by Pitman (in litt.), outranking the sunbirds for which I have com- 

 piled larger numbers of such records. 



Klaas's cuckoo agrees with the didric in that it has not been found 

 to lay its eggs in nests of terrestrial nesters (larks, typical pipits, etc.) 

 in treeless savannahs and also in that it usually avoids the nests of 

 bulbuls and babblers. There is a single record for a single species of 

 each of these families. 



List of all known host species: 



Motacilla aguimp Pied wagtail 



Motacilla capensis Cape wagtail 



