102 U.S. NATIONAL MUSEUM BULLETIN 223 



pends on the number of nests available, and I doubt if each whydah 

 lays more than four or five eggs. No attempt is made to destroy 

 the eggs of the foster bird, nor does the nestling Vidua eject any of 

 the rightful chicks." In an earlier paper van Someren (1922, p. 153) 

 wrote that he had "seen the female accompained by the male enter 

 the nest of an EstrUda, deposit its egg, and then fly off with the male." 

 In his 1956 account, he stated that he saw "the male accompanying 

 the hen to two known Estrilda nests. Quite often, in the vlei land, 

 I have seen a male fly from a bush and drop to a certain patch of 

 grass, then leave (from there) with a hen. That patch has held an 

 Estrildu nest. I have located waxbills' nests by watching the move- 

 ments of the hen and cock pintail." It would seem that if the female 

 often removed one of the eggs before depositing its own, van Someren 

 would have seen some sign of it. 



Delacour and Edmund-Blanc (1934, p. 85) wrote that the hen pin- 

 tail accompained by the cock enters the nest of the host and lays its 

 egg. There is no indication that these authors had any original ob- 

 servations on this point, and their statement is probably based on 

 V. G. L. van Someren's published notes. Probably the male pintail 

 does not actually enter the nest together with its ovulating mate. 

 In the northern Transvaal near Potgieters Rust, I saw a male in full 

 breeding plumage near a waxbill's nest (about 2 feet from it, in the 

 same bush) from which a female pintail flew as I approached, and 

 was joined in flight by the male. The nest proved to be empty. 



Mors (1925, p. 168) watched a hen pintail go into a nest of a common 

 waxbill from which it did not emerge until about half an hour later. 

 The time elapsed is much more than would be required merely for 

 egg-laying, but no indications were given about what the bird was 

 doing. On examination the nest was found to contain five eggs of 

 the waxbill and two of the pintail. 



Nothing is known of the number of eggs laid by one hen in a 

 season. I have never found more than fom- discharged follicles in 

 the ovary of any bird, but there is no evidence whether the bird may 

 lay the equivalent of more than one clutch a season with a sufficient 

 interval between clutches to allow the follicles time to disintegrate. 

 Similarly we do not know whether one female lays all its eggs in 

 nests of a single species of victim, but since the great majority of known 

 instances of its parasitism involve a group of closely related waxbills 

 and fire-finches, this question of definite host specificity may be less 

 important here than in other brood parasites, such as cuckoos and 

 cowbirds. 



Years ago A. Roberts (1912, pp. 45^6) wrote that the hen pintail 

 may first deposit her egg on the ground and then carry it to the nest 

 of some other bird; however, he based this erroneous guess on the 



