NO. 5 THE YELLOW-RUMPED TANAGER — MOYNIHAN II 



If the individual patterns retain the same functions when they are 

 uttered together as when they are uttered separately (and my obser- 

 vations would suggest that they do), then the "Tzzheet" — Thin Rattle 

 — Hoarse Flourish performances probably function as "song," as the 

 term is used in this series of papers. When uttered by a bird of one 

 sex they may attract birds of the opposite sex and repel other birds 

 of the same sex. 



Adult male yellow-rumped tanagers frequently interrupt their 

 Dawn Calling to utter purely or predominantly hostile notes. Such 

 ambivalent performances may subserve the same functions as stereo- 

 typed "Tzzheet" — Thin Rattle — Hoarse Flourish patterns, but they 

 are extremely variable in form and do not seem to be ritualized per se. 

 Yellow-rumped tanagers apparently do not utter stereotyped series of 

 Nasal Notes and "Tzzheet" Notes (or any other primarily sexual 

 pattern) in regular alternation like the series of Nasal Notes and 

 "Tseeet" Notes uttered by adult male crimson-backed tanagers. 



The "Tzzheet" Note — Thin Rattle — Hoarse Flourish complex, as 

 a whole, is remarkably similar to the equally stereotyped Rattle — 

 Flourish performances of brown-capped bush-tanagers. The rattling 

 and Flourish parts of the sequences of the two species certainly are at 

 least partly homologous. The Rattle — Flourishes of brown-capped 

 bush-tanagers are often preceded by "Tsit" Notes. These "Tsit" 

 Notes, when uttered by themselves alone, do not appear to be as 

 strongly sexual as the "Tzzheet" Notes of yellow-rumped tanagers, 

 but their association with Rattle — Flourishes would suggest that 

 they may be phylogenetically related to "Tzzheet" Notes (and the 

 Plaintive Notes of other species). This suggestion may be supported 

 by the fact that sooty-capped bush-tanagers utter similar sounding 

 "Tsit" Notes to call in or attract mates. 



Yellow-rumped tanagers also utter rattling sounds which are very 

 much softer than either typical pure Rattles or typical Thin Rattles. 

 These may be called Muffled Rattles. They are rarer than the other 

 kinds of Rattles, usually prolonged, and associated with vigorous 

 reactions between individuals in close proximity to one another. 

 They seem to be uttered most frequently by adult males approaching 

 or being approached by adult females or juveniles at the height of the 

 breeding season. Once I heard an adult male utter a Muffled Rattle 

 immediately before an apparently successful copulation. Many similar 

 or identical patterns were uttered during an unusually prolonged and 



latter are also, of course, intermediate between simple Thin Rattles and Hoarse 

 Flourishes.) 



