16 U.S. NATIONAL MUSEUM BULLETIN 223 



plumage and display although used in territorial defense have been 

 evolved primarily with respect to species recognition in mate 

 selection," ^° 



Moreau and Moreau (1938, pp. 314-327) found, in Euplectes 

 nigroventris and E. hordeacea, that the size or position of the territory 

 bears no relation to the availability of food for adults or young. In 

 the latter species the territory is apparently always fairly large in 

 size, from 600 to 1,200 square yards, and the size of the area appears 

 not to be affected by the abundance of breeding males. On the other 

 hand, in E. nigroventris the territory is seemingly indefinitely com- 

 pressible. Sometimes fully functional territories measure less than 

 10 square yards. "Irrespective of the size of his territory a male E. 

 nigroventris has up to five breeding females active in it at once, and 

 may raise eight families in it during the season. In a territory of 

 E. hordeacea not more than three breeding females have been found 

 at once. In the breeding population of both species females out- 

 niunber males by quite fom* to one." 



In the red-billed weaver, Quelea quelea, Morel and Bourhere (1955 

 and 1956) described an interesting picture of territorial and mating 

 relations. The species is colonial and nests in large groups, and the 

 males outnumber the females three to one. Ten colonies, destroyed 

 with explosives in order to kill all the birds without allowing any to 

 escape, revealed 2,749 males and 946 females. In defense of the use 

 of this technique, it should be noted that the studies of Morel and 

 Bom-liere were part of a campaign to control this species, which had 

 become a very serious agricultural pest in the grain growing areas 

 of Senegal. 



This uneven sex ratio seems to be a result of differential post- 

 nestling mortality, as extensive examination of newly hatched or 

 nearly fledged young show nearly equal numbers of males and females. 

 In one colony with 525 nestlings 1 to 2 days old, 279 were males and 

 246 were females. Another colony with 323 nestlings, had 159 

 males and 154 females. Another colony with 182 nesthngs about 8 

 days old showed 86 males and 96 females. Another colony wdtli 136 

 nestlings had 71 males and 65 females. 



The males build the nests, and pairing takes place after the nests 

 are built, but the females may occasionally visit the nests even before 

 they are completed. The courtship behavior is of a mutual type, 

 which may possibly help in the social coordination in the colony. 

 Since the birds appear to be strictly monogamous, the fate of the 

 surplus males remains a mystery. 



'" That this sort of arrangement Is not necessarily restricted to species with highly distinct male and closely 

 similar female plumages is indicated by Lanyon's (1957) findings in the two extremely similar species of 

 Sturnella. 



