62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I43 



backed tanagers have rather similar habitat preferences. Both species 

 occur in young second-growth forest and scrub relatively more fre- 

 quently than do such species as the plain-colored tanager, the palm 

 tanager, the green honeycreeper, and the Cyanerpes honeycreepers. 



Crimson-backed tanagers are usually very noisy and often travel in 

 family groups or small flocks of several family groups. Mixed flocks 

 that include crimson-backed tanagers are particularly conspicuous and 

 tend to attract a wide variety of birds of other species not usually 

 associated with such flocks. The other species attracted by crimson- 

 backed tanagers are not usually the same as those attracted by red- 

 legged blue honeycreepers. Crimson-backed tanagers seem to be espe- 

 cially attractive to several orioles and flycatchers. 



SUMMER TANAGER 



The social role of summer tanagers in mixed blue and green tanager 

 and honeycreeper flocks is very different from the corresponding roles 

 of any other tanagers or honeycreepers. In Panama summer tanagers 

 seldom associate with one another. It is relatively rare to see more 

 than a single summer tanager in any given area at any given time. 



These single summer tanagers become associated with mixed species 

 flocks relatively frequently. They are probably associated with all 

 types of blue and green tanager and honeycreeper flocks and with 

 several other types of mixed flocks almost equally frequently (see 

 below). They seem to discriminate between different types of mixed 

 species flocks only insofar as they prefer flocks that inhabit the edges 

 of forest or scrub and include some insectivorous or partly insec- 

 tivorous species. They are largely insectivorous themselves in lowland 

 Panama, and are most common along the edges of forest and scrub. 



Summer tanagers are seldom very conspicuous in mixed flocks. 

 They are usually silent as long as they are associated with individuals 

 of other species, and tend to remain on the outskirts of mixed flocks. 

 While they are associated with mixed blue and green tanager and 

 honeycreeper flocks, they are sometimes joined and followed by indi- 

 viduals of other species, especially such species as the green honey- 

 creeper and the palm tanager which have particularly strong joining 

 and following tendencies; but it is my impression that they usually 

 become associated with such flocks in the first place because they them- 

 selves join the flocks. 



The usual role of summer tanagers in mixed blue and green tanager 

 and honeycreeper flocks is reminiscent of the roles of many furnariids 

 (or dendrocolaptids) in other types of mixed flocks (see below). 



