PARASITIC WEAVE RBIRDS 19 



subauretis,^^ and velatus^^). While P. spilonotus is here listed on the 

 basis of published observations, it was recently shown to be con- 

 specific with P. cucAillatus, which is listed below as a species with 

 both sexes taking part in nest construction. Either our available 

 data on P. spilonotus are incomplete or we have here a case of racial 

 difference in so far as nesting activities are concerned. 



How compulsive nest building may become is illustrated by an 

 instance (recorded by Bannerman, 1949, p. 146) of two males of 

 Malimhus scutatus actually working on the same nest at the same time. 

 Usually, these weavers make them alone. 



In most of these birds, the females may do some work on the nest 

 lining, but apparently not more than this much is the rule. On the 

 other hand, both sexes take part in nest construction in Quelea cardi- 

 juilis, Ploceus brachypterus ^ and Ploceus cucullatusP In the estril- 

 dines, both sexes help build in Estrilda cyanocephala if and when they 

 cannot find a deserted ready-made nest of another species. 



The instance cited above of two Malimhus males building the same 

 nest is duplicated by examples in the Estrildinae. Thus, what appears 

 to be communal nest building sometimes takes place in Spermestes 

 nigriceps^° (Moreau and Moreau, 1939, pp. 318-319), although there 

 is no evidence that a nest constructed by more than one bird is ever 

 finished or used. 



In one striking example seven birds of different ages, two adults, one bird with 

 mottled head, and four juveniles, all helped to build one nest, M'hile a few yards 

 away another was being built by a single adult. . . . Several times an adult 

 arrived followed by three juveniles, all carrying the grass. Often the adult took 

 the grass a young bird brought and built it in, but at other times the young placed 

 theirs themselves after the adult had done so, and apparently in imitation of its 

 action. . . . The birds were working so energetically that at one time the 

 adult was arriving every twenty seconds with material. . . . Forty visits with 

 material were made in thirteen minutes, and at one time five birds were all on the 

 half-made nest at once. 



In captivity many weavers that have not actually bred there never- 

 theless weave straws and raffia to such an extent as to fill all available 

 sites with untidy masses of woven matter. I have seen this activity 

 repeatedly with such birds as Quelea quelea and Ploceus rubiginosus.^^ 

 The mere sight of one bu'd carrying nesting materials or weaving them 

 into place seems to be a sufficient stimulus to activate the other indi- 

 viduals present to similar efTort. 



2« Ploceus subaureus A. Smith, Dlustrations of the zoology of South Africa .... vol. 2, Aves, 1839, pi. 30, 

 fig. 1 (Algoa Bay). 



2' Ploceus velatus Vieillot, Nouveau dictioimaire d'historle naturelle, vol. 34, 1819, p. 132 (Namaqualand). 



25 Ploceus brachypterus Swainson, Birds of western Africa, vol. 1, 1837, p. 168, pi. 10 (Senegal). 



2» Oriolus cucullatm P. L. S. MQller, Des Ritters Carl von Lian6 . . . vollstandige's Natursystem . . . , 

 Supplement, 1776, p. 87 (Senegal). 



'0 Spermestes nigriceps Cassin, Proc. Acad. Nat. Sic. Philadelphia, for 1852, p. 185 (Zanzibar). 



" Ploceus rvhiginosxis Rflppel, Neue Wirbelthiere zu der Fauna von Abyssinien gehorig, entdeckt und 

 beschrieben. V5gel, 1840, p. 93, pi. 33, flg. 1 (Abyssinia). 



