356 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 30 



greater part, descriptions written one year mean little or nothing the 

 next! What I have termed the announcement of presence call is 

 uttered before courtship begins, when, for example, the male is alone 

 in the nest tree. I write it as " agua " or " waco " or " chap-pa- 

 qua"; "hope you choke." ^^ The tone is loud, deep, liquid, and 

 gurgling and the call is usually interspersed with " chucks." The 

 courtship, or " crash " call, which I consider the male's real song, 

 begins with the one just described and adds a sputtering crackle 

 ending in an explosive crash. In my notes I have also termed this 

 remarkable production a sputtering, masticatory ejaculation. The 

 polysyllables help convey some idea of its character. This call, as 

 described under courtship, is given with obvious muscular effort. 

 It can, indeed, be seen coming as the bird's body begins to swell 

 from below upward and, rising on tiptoe, he delivers his vocal 

 appeal, then sinks back deflated. Of all these themes there are 

 endless variations and combinations and as the season advances 

 changes occur which, while evident to the ear, are too subtle to be 

 put on paper. 



WING " NOTES " 



The flight of the female is essentially noiseless, but the flight of 

 the male is often accompanied by a sound, evidently produced by 

 the passage of the widely radiating, emarginate outer primaries 

 through the air. This sound varies in rhythm in response to the 

 character of the bird's flight. It is apparently under the bird's 

 control and may be withheld, when the flight of the male is as noise- 

 less as that of the female. It probably has some sexual significance. 

 As a rule it marks the time of the bird's wingbeat as with a loud 

 "fluff, fluff, fluff," he flies steadily with even strokes or passes on 

 deep, swinging loops. When the male pursues the female in court- 

 ship-flight it is a loud startling, rushing roar, such as might be 

 produced by the sudden violent tearing of some textile. On sev- 

 eral occasions it accompanied a peculiar flight as the bird pointed 

 its bill toward the ground and, with short, jerky wingbeats, pro- 

 duced a staccato " plop, plop, plop." This may have been some 

 form of sexual display. 



THE QUESTION OF TERRITORY 



The question of territorial rights while nesting apparently does not 

 enter into the location of an oropendola colony. On Barro Colorado 

 three nesting colonies of these birds are known. One is 400 yards 

 from the laobratory colon}'^, the other nearly two miles from it in the 



" The latter phrase Is the only one that has held In my notes for two years and for this 

 reason I give it. 



