PARASITIC WEAVE RBIRDS 109 



Roberts there were no eggs of the host; all of this waxbill's eggs 

 were replaced by the parasitic ones while the nest was under observa- 

 tion. Unfortunately, Roberts failed to record his observations of 

 this unusual case history, other than to state that the nest was 

 deserted eventually. This was at Kilgobbin, Natal, early in February. 

 The two Karkloof sets, taken in January and February, each had 

 two waxbill eggs as well as the five parasitic ones. 



On April 3, near Taveta, Kenya, I found a nest of this 

 waxbill containing four eggs of the owner and one of the pintail. The 

 next day the nest was empty and deserted, probably because of some 

 predator. Another nest, found a week later, with four eggs of the 

 waxbill and one of the parasite, also came to grief within the next few 

 days. 



In Nyasaland Belcher (1930a, p. 333) found eggs of the pintail in 

 about 40 percent of all the nests of the waxbill (race cavendishi) 

 seen. In the MarandeUas area, Southern Rhodesia, Neuby-Varty 

 (in litt.) found eggs of the parasite only in nests of this waxbill. VvTiile 

 these findings do not imply that no other birds were parasitized, they 

 do suggest something of the relative frequency that the common wax- 

 bill is used as the host. That it is the commonest victun in Zululand 

 as is indicated by an old Zulu saying that a young pintail is reared out 

 of every nest of the waxbill (A. Roberts, 1907, pp. 9-11). 



In the Transvaal Mors (1925, p. 168) found that most nests ex- 

 amined of this waxbill contained eggs of the pintail, and concluded 

 that an unparasitized nest was a relative rarit}^. For further details 

 involving instances of this host species, reference maj^ be made to 

 the account of the development of the nestling pintail (pp. 113-116). 



Although this waxbill is very frequently victimized by the pintail, 

 no one seems to have found mixed flocks of adults of the two species 

 even in areas where both species are numerous. Skead (in litt.) in- 

 formed me that he saw a juvenal pintail with a flock of about 40 adult 

 waxbills feeding on the ground. Numbers of observers have seen 

 mixed groups of young birds of the two species, but once they pass 

 the postju venal molt, they seem to part company. 



It may be mentioned that this waxbill makes a nest with a secondary 

 chamber above, in which the cock bhd is said to sleep, and which is 

 almost never used for eggs. There are no records of a pintail ever 

 making the mistake of laying an egg in this false nest cavity; she 

 seems to know the real nest from this roosting cavity. 



Grey waxbill: Estrilda troglodytes (Lichlenstein) ^ 



I note one very uncertain record. Chapin (1954, pp. 557-558) 

 gave the measurements of a set of six eggs of the gray waxbill as vary- 



' Fringilla troglodytes Lichtcnstein, Verzeichnlss dcr Doubletten des zoologischen Museums . . ., 1823, 

 p. 26 (Senegambla). 



