6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 149 



tendencies. The two tendencies are probably more nearly equal in 

 strength during Hoarse Screams than during either Nasal Notes or 

 pure Rattles. Softer and shorter Hoarse Notes are uttered during 

 intraspecific encounters. In the course of the present investigation 

 they were heard most frequently during encounters between adult 

 males and (known or presumed) females. They were uttered by males 

 approaching or being approached by females, usually or always when 

 the males were not very familiar with and/or obviously hostile toward 

 the females. Some of these notes were combined with Gaping or 

 actual attack movements. Similar notes certainly are uttered by both 

 adult females and juveniles, although more rarely, in some hostile or 

 partly hostile circumstances ; but I cannot say very much about them, 

 primarily because they are so soft that I may have missed many of 

 them in the field. All these comparatively soft Hoarse Notes must 

 be purely hostile or produced by simultaneous activation of both 

 hostile and sexual tendencies. They probably are produced when the 

 attack and escape tendencies are nearly equal to one another but 

 weaker than when loud Hoarse Notes are uttered. If a sexual tendency 

 is also involved, it is almost certainly relatively weak. 



Adult males may utter slightly different "Greeting" Notes when 

 joining or being joined by females with whom they are on fairly good 

 terms. In their most typical form these notes are slightly hoarse in 

 quality, but less so than the typical Hoarse Notes described above, 

 and without any rattling undertone. They are very soft and apparently 

 always uttered in series. Typical series might be transcribed as "Tsee- 

 whee-hee" or "Zhee-wee-tsee-tseewee" or "Zee-a-waa-zaa-waa." All 

 these patterns sound intermediate between typical Hoarse Notes on 

 the one hand and Hoarse Flourishes and/or "Tzzheet" Notes on the 

 other hand. They certainly intergrade with the former and probably 

 with the latter. The only birds heard to utter typical "Greeting" 

 Notes were captive individuals kept in aviaries on Barro Colorado 

 Island ; but the notes are so soft that one would not expect a human 

 observer to be able to hear them in the field. They probably are 

 produced by the same hostile motivation as typical soft Hoarse Notes, 

 with an added (or stronger) sexual component. The possession of a 

 special "Greeting" pattern, obviously related to Hoarse Notes but 

 apparently uttered only during encounters between males and females 

 of the same species, may be another special resemblance between 

 yellow-rumped tanagers and brown-capped bush-tanagers. 



Among the most common vocal patterns of yellow-rumped tanagers 

 are short, monosyllabic, rather high pitched and hard sounding notes 



