NO. 7 FLOCKS OF NEOTROPICAL BIRDS — MOYNIHAN 55 



preferences of some species for plain-colored tanagers, but equally 

 strong in its way. 



As red-legged blue honeycreepers are the most common birds in pre- 

 dominantly honeycreeper flocks (see below), green honeycreepers 

 tend to perform many more supplanting attacks in such flocks than 

 in predominantly tanager flocks. 



We were not able to study the social relations between green honey- 

 creepers and blue dacnises in detail, as the latter were rather rare on 

 Barro Colorado Island, the only area where green honeycreepers were 

 observed with appreciable frequency during the course of the present 

 investigation ; but our observations suggest that green honeycreepers 

 react to blue dacnises in a way that is more like their reaction to 

 plain-colored tanagers than their reaction to red-legged blue honey- 

 creepers. We saw green honeycreepers join and follow, or attempt 

 to approach, blue dacnises relatively frequently, but we did not see 

 them supplant them. This latter fact may be particularly significant be- 

 cause blue dacnises are appreciably smaller than green honeycreepers. 



The social relations between green honeycreepers and bananaquits 

 are essentially intermittent. Sometimes the former seem to ignore the 

 latter almost completely, but at other times they may attempt to join, 

 follow, and/or supplant them very frequently and persistently. (The 

 probable explanation of this peculiar relationship is discussed below in 

 connection with the social role of bananaquits.) 



Green honeycreepers join such birds as plain-colored tanagers and 

 bananaquits quite frequently without beginning to feed immediately 

 afterward, even when they are not obviously very aggressive. 



Female green honeycreepers are usually more aggressive than 

 males; and there are some indications that they are associated with 

 mixed flocks slightly less frequently than are males. 



It will be noticed that relatively few cases of joining, following, and 

 supplanting by green honeycreepers are included in the accompanying 

 tables. This might convey a somewhat misleading impression, as green 

 honeycreepers do attempt to join, follow, and supplant individuals 

 more frequently than the figures in these tables would suggest. The 

 apparent discrepancy may be explained in several ways. Most of the 

 flocks observed when these counts were made were predominantly 

 tanager flocks, in which green honeycreepers perform fewer overt 

 reactions to individuals of other species than in other types of mixed 

 flocks. Individuals of other species also tend to react to green honey- 

 creepers by attempts at evasion. They often fly away, or at least hop 

 to another branch, when they see a green honeycreeper approaching, 



