NESTING HABITS OF OROPENDOLA — CHAPMAN 357 



opposite direction. Birds apparently en route to the nearer colony 

 sometimes stop in the laboratory tree and min«2jle with the local birds 

 without their presence bein<r questioned. 



Nor do «i;roups within the colony appear to be concerned by the 

 question of boundaries. The first bird to arrive selects its p^oup loca- 

 tion from the unoccupieil held, the choice bein<^ made by the females. 

 Each year of my observations the first «^roup to arrive has selected a 

 different location. Always, however, a situation was chosen that had 

 been used before. Here the point of attachment, which is usually all 

 that is left of the precedin<;j year's nest, offered an attractive place 

 for the be<:;inninfj: of a new nest. 



The nests are al\va3^s built on the southerly and westerly, which is 

 the leeward, side of the tree during the period of trade winds that pre- 

 vail in the dry season. Here the nests receive some protection from 

 the windward side of the tree, and it is probable that the birds can 

 enter them more readily flying upwind than they could when flying 

 down wind. 



The tree is large enough to afford sufficient space for subsequent 

 groups without arousing the enmity of those already located, and I 

 have seen no ill-feeling displayed between the members of different 

 groups as such. Size is, indeed, to be desired in a colony, and the 

 larger its population the more protection do its component individuals 

 receive from their common enemies. 



It was soon evident that the birds were not monogamous, but it was 

 by no means clear whether they were polygamous or promiscuous. 

 The relationships of the males to one another were also to be deter- 

 mined. No reference to these subjects has been found in the literature 

 concerning oropendolas and caciques. 



COURTSHIP AND SEXUAL RELATIONS 



To determine the sexual or marital relations of the members of an 

 oropendola colony is one of the most interesting and at the same time 

 most difficult problems connected with the study^of these birds. At 

 the time of my departure the colony of 1926 contained about 6 or 7 

 males and 39 females; tiiat of 1927, 5 or males and 29 females; that 

 of 1928 was never fully organized. In each case the number of 

 females given was determined by the number of nests. Unattache<l 

 females may have visited the nest tree, but they did not function as 

 members of the colony. 



The opening of the nesting season is announced by the location call 

 of the male, given from the nest tree, on numbers of occasions, some 

 days before nesting actually begins. Females may or nuiy not be 

 present at such times; however, should there be any in the tree the 

 male pays no attention to them. It is not until they begin to build 

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