NO. 7 FLOCKS OF NEOTROPICAL BIRDS — MOYNIHAN 5 1 



frequently is the palm tanager. In many areas blue tanagers continue 

 to associate with mixed flocks more frequently than do palm tanagers 

 during the breeding season, as the nesting sites of blue tanagers are 

 usually less isolated than those of many palm tanagers. In such areas, 

 during the breeding season, blue tanagers tend to join and follow 

 individuals of other species much more frequently than they are 

 joined and followed by individuals of other species. The role of 

 blue tanagers in mixed flocks is much more consistently "active" in 

 such circumstances than when palm tanagers are also frequently asso- 

 ciated with mixed flocks. 



In an earlier paper (Moynihan, i960) it was stated that there are 

 usually more palm tanagers than blue tanagers in mixed flocks. Subse- 

 quent observations would indicate that this is not generally true (see 

 accompanying tables). 



Blue tanagers appear to have a definite interspecific preference for 

 plain-colored tanagers. This is probably similar to the corresponding 

 preference of palm tanagers in quality, but averaging somewhat 

 weaker. Blue tanagers also seem to have a special interspecific prefer- 

 ence for palm tanagers themselves. This may be almost or quite as 

 strong as the reciprocal preference of palm tanagers for blue tanagers, 

 and equally similar in quality ; but it is usually weaker than the prefer- 

 ence of blue tanagers for plain-colored tanagers. 



GOLDEN-MASKED TANAGER 



Golden-masked tanagers were not observed very often during the 

 present study. When they were seen with mixed flocks they showed a 

 definite tendency to join and follow plain-colored tanagers. They may 

 also have shown a very slight special interspecific preference for blue 

 tanagers. (It may be significant that both golden-masked and blue 

 tanagers have considerable amounts of bright blue in their plumages. 

 The golden-masked tanager, the Panamanian form of the blue tanager, 

 and the plain-colored tanager all have bright blue flash patches on 

 the wings, which are revealed very conspicuously in flight.) 



GREEN HONEYCREEPER 



The behavior of green honeycreepers in mixed flocks is reminiscent 

 of palm tanagers and blue tanagers; but by no means absolutely 

 identical. Some aspects of the social role of green honeycreepers in 

 mixed flocks are very distinctive. Like the palm and blue tanagers, 

 green honeycreepers occur in mixed flocks quite frequently and tend 



