NO. 5 THE YELLOW-RUMPED MANAGER — MOYNIHAN 20, 



One of them was particularly interested in a female silver-billed 

 tanager, while the other seemed to have formed pair-bonds with a 

 juvenile black- throated tanager (R. nigrogularis) . 



The orange-rumped tanagers were observed to perform Flicking 

 movements, Gaping, Head-ruffling (see figure 4d), Back-ruffling, 

 Belly-fluffing, and "silent song," and heard to utter Nasal Notes and 

 Rattles. Some of these patterns, e.g. the Nasal Notes, were apparently 

 identical with the corresponding displays of Panamanian yellow- 

 rumped tanagers. Others differed to some (usually slight) extent. 

 Some of the differences are listed below. 



Both orange-rumped tanagers performed silent Gaping rather 

 more frequently than the yellow-rumped tanagers kept in captivity 

 on Barro Colorado Island. Much of this Gaping was done with the 

 head lowered and the neck stretched forward. A Gaping bird usually 

 faced straight toward the other bird releasing the performance. The 

 combination of Gaping with lowering of the head and stretching of 

 the neck may have been ritualized per se to form a "head forward 

 threat" display like that of many other passerines (see Andrew, 

 1961). Once a bird in this posture looked downward. This was 

 reminiscent of the Head-down display posture of yellow-rumped 

 tanagers (except that the Gaping was maintained throughout). 



Once a bird was seen to perform Back-ruffling that involved the 

 black feathers of the center of the back as well as the orange feathers 

 of the rump and lower back. 



The most extreme Belly-fluffing observed is shown in figure 5c 

 This is considerably less extreme than the most exaggerated Belly- 

 fluffing of yellow-rumped tanagers or crimson-backed tanagers, but 

 it may well have been low intensity. 



All the Rattles sounded like the pure Rattles of yellow-rumped 

 tanagers. 



Both orange-rumped tanagers also uttered moderately loud (but 

 not metallic) notes that might be transcribed as "Whit" or "Tsit." 

 They were uttered singly and in series when the birds were more or 

 less isolated (as much as possible within the aviaries), and were not 

 accompanied by overt indications of alarm. This would suggest that 

 such notes are largely or completely homologous with the "Tzzheet" 

 Notes of yellow-rumped tanagers, not the softer "Tsit" Notes uttered 

 by one yellow-rumped tanager in captivity. Sometimes single moder- 

 ately loud "Whit" or "Tsit" Notes were uttered immediately before 

 and/or immediately after Rattles. Such compound calls presumably 

 are related to the "Tzzheet" — Thin Rattle — Hoarse Flourish per- 



