NO. 5 THE YELLOW-RUMPED TANAGER MOYNIHAN 9 



may be uttered by themselves alone or in a variety of obviously 

 unritualized associations with many other vocal patterns, or in a close 

 and apparently ritualized association with typical "Tzzheet" Notes 

 and Thin Rattles. The latter performances seem to be something of a 

 special case, and will be discussed separately below. The other Hoarse 

 Flourishes are uttered almost exclusively by adult males and are 

 particularly characteristic of the height of the breeding season. They 

 are uttered in much the same way and in much the same circum- 

 stances as melodious "Kioo" or "Klioo" Notes. They are almost 

 always uttered by isolated birds, singly, at any time of the day or in 

 Dawn Calling series. They are, in fact, the most common of the 

 Dawn Calling notes at the height of the breeding season, much more 

 common than "Kioo" or "Klioo" Notes. Many Dawn Calling per- 

 formances are composed of Hoarse Flourishes alone. Less fre- 

 quently Hoarse Flourishes and "Kioo" or "Klioo" Notes are uttered in 

 regular alternation. Typical Hoarse Flourishes intergrade with both 

 typical "Tzzheet" Notes and typical "Kioo" or "Klioo" Notes. All 

 this would suggest that Hoarse Flourishes are really intermediate 

 between "Tzzheet" Notes and "Kioo" or "Klioo" Notes, produced 

 by intermediate motivation. They certainly function as another sum- 

 mons to call in or attract mates. 6 



Thin Rattles are uttered by adult yellow-rumped tanagers of both 

 sexes and by juveniles. A typical Thin Rattle sounds very much 

 like a pure Rattle but is higher-pitched on the average and "thinner" 

 in sound, less penetrating but not necessarily softer. Some Thin 

 Rattles seem to remain at the same pitch throughout. In others 

 the pitch declines gradually and continuously but only slightly. They 

 all sound perfectly intermediate between typical pure Rattles and 

 typical "Tzzheet" Notes, like more or less prolonged "Tzzheet" 

 Notes which have broken up or like pure Rattles which have been 

 transposed into a higher key. They also intergrade with both "Tzzheet" 

 Notes and pure Rattles. They are frequently associated with both 

 overt hostility, especially aggression, during disputes between indi- 

 viduals of the same as well as opposite sex, and with a variety of 



6 The Hoarse Flourishes of yellow-rumped tanagers are somewhat similar 

 to the Flourishes of Chlorospingus spp. in form, motivation, and function. They 

 may be completely homologous with the latter. If, however, their hoarse quality 

 is an indication that an hostile component is involved, then the homology prob- 

 ably is only partial. In any case, the relationship between the Hoarse Flourishes 

 of yellow-rumped tanagers and the Flourishes of Chlorospingus spp. probably 

 is exactly the same as the relationship between the "Tzzheet" Notes and the 

 Plaintive Notes of the same species. 



