104 U.S. NATIONAL MUSEUM BULLETIN 223 



that out of over 100 individuals only 2 died in the period of a year. 

 It is probable that he was referring to weaverbirds in general, and 

 not specifically to the pintail. 



Hosts 



The known hosts of the pintail are all species of weavers with the 

 exception of two warblers and two finches — a fairly limited range of 

 related type birds. With the exception of the finch, all these birds 

 have domed nests with openings on the side. There are enough data 

 on the pintail, and on the commoner warblers, flycatchers, thrushes, 

 and bulbuls to enable us to say that this limited choice of hosts is 

 real and not merely due to insufficient observations. The birds 

 parasitized are generally small species, most of them being about the 

 same body size as the parasite or even smaller, and in most cases the 

 eggs of the host are somewhat smaller than those of the parasite. 

 Over 77 records for all hosts refer to 18 species, or 26 forms includ- 

 ing races, and do not include 3 other species that cannot be con- 

 sidered definitely established as victims. Of the 18 species, 11 are 

 waxbills, fire finches, or mannikins; 1 is a long-tailed whydah; 2 

 are larger weavers; 2 are true finches; and 2 are grass warblers. The 

 identifications of the parasitic eggs are by no means always as definite 

 as I would wish. They are individually appraised as far as the avail- 

 able evidence permits. Of the 77 records, all but a few relate to 

 waxbills; in fact 41 are for one species, the common and widely 

 distributed Estrilda astrild (and races). 



Considering the very great geographic range of the pintail, the re- 

 corded list of victims of its parasitism amounts merely to the begin- 

 ning of a definitive list of hosts. There are some species not on the 

 list whose absence is surprising, because they would seem to be as 

 suitable as some that do appear in the subjoined list and whose nests 

 have been examined in sufficient numbers to make it apparent that 

 they are not victimized (at least not to any extent). The cordon bleu, 

 Estrilda angolensis, is such a species. In fact, Plowes (1947, p. 153) 

 examined many nests of this bird at Ladysmith, Natal, where the 

 pintail is common, and was led to conclude that the pintail does not 

 make use of the nests of the cordon bleu. On the other hand, the 

 waxbills, fire finches, and their close relatives (the most "likely" vic- 

 tims) all lay small pure white eggs similar to those of the pintail, 

 and it is quite possible that the eggs of the latter may have been 

 overlooked. 



That more than half the cases of parasitism of the pintail have to 

 do with the common waxbill supports K. Neunzig's contention (1929b, 

 pp. 3-6) that it is the usual, "normal" host. There is ample evidence, 

 however, that it is by no means the only one, as may be seen from 



