Evolution of Brood Parasitism 

 in Weaverhirds 



THAT PARASITIC REPRODUCTION OCCURS ill the weaverbirds was 

 first made known in 1907 by A. Roberts/ writing about the pin- 

 tailed widow bird, Vidua macroura, in South Africa. Shortly after- 

 ward, Jackson and his native collector, Baraka, made similar observa- 

 tions on this species in East Africa, and subsequently IVIors and 

 V. G. L. van Someren produced still further evidence. Roberts (1917) 

 and van Someren (1918) also reported almost simultaneously that 

 the cuckoo finch, Anomalosjpiza imberbis, was also parasitic. Since 

 then the same habit has been found in other species of Vidua and in 

 the paradise widow bird, Steganura paradisaea. Of not one of these 

 species is our present knowledge more than partial; of some it is still 

 extremel}^ fragmentary. These birds offer the natm'alists resident 

 in Africa a real opportunity for rewarding work. 



Phylogenetic Background 



In approaching the problem of the evolution of brood parasitism in 

 viduine weavers and in Anomalospiza, I must first establish a frame 

 of reference on which to peg pertinent data. I must first show where 

 these birds fit in the overall pictm-e of the family and what their 

 ancestry within that group may have been. 



We are fortunate in having two comprehensive discussions of ploceid 

 taxonomy — 'One by Chapin (1917) and one by Sushkin (1927) — the 

 first based on extensive acquaintance with a large number of the 

 included genera and species in life as well as in the museum, and the 

 second couched in terms of the skeletal anatomy of the group. Chapin 

 was the first to use characters such as the pattern of the mouth mark- 

 ings of the nesthngs, the type of nest constructed, and the presence or 

 absence of seasonal plumage changes — all of which have been found 

 to be more revealing of true relationsliips than such overemphasized 

 "museum" characters as the relative length of the outermost primary. 

 Sushkin's conclusions provided complementary information concern- 



' At this time there was in the literature an unverified belief that the red-billed weaver, Quelea quelea, 

 might also be a brood parasite. This belief since disproved, was based upon the fact that although the bird 

 was very abundant, no one had found and described its nest. Since then, large breeding colonies have been 

 located and studied in considerable detail. 



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