374 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 19 3 



tempts were made b}'' single birds of this group to enter nests but 

 they were prevented by Zarhynchus. Finally all left together in 

 the usual long flight. 



The male Camidix was recorded on only three occasions, January 

 19, 1927, February 10 and 19, 1928. On the first-named date a male 

 was accompanied by three females before which he slightly expanded 

 his ruff. On February 10 there were also three females with a single 

 male. On February 19 there was only one female with a single male. 

 The actions of these birds seemed to indicate that more than a pass- 

 ing relation existed between them and I quote my description of it : 



Seven-thirty a. m. A male and female Cussidix in the top of the sand-box 

 tree. The male's plumage glistens brightly and he is conspicuously the larger 

 of the two. Some minutes after I discovered them the female started alone, 

 circled the tree twice in a rising spiral flight, then headed east. The male 

 continued preening. In about three-quarters of a minute a female alighted 

 near the male and half a minute later started due east. He followed. Assum- 

 ing that there was only one female, did she circle on her first flight while 

 awaiting for the male to follow? Did she return because he did not? 



Cassidix is obviously recognized as a common enemy not only 

 when she seeks to enter a nest, but when, early in the nesting season, 

 she enters the nest tree. Not alone the bird whose nest is threatened 

 but other birds in the same group, and also from other groups, join 

 in attacking her; while Legatus assails at times with more zeal than 

 Zarhynchus. An incident illustrating these facts is recorded in my 

 journal for February 7, 1926 : 



At 4 p. m. a female Cassidix tried to enter several nests but so clumsily that 

 before she discovered the combination she was driven off by a combined attack 

 of several female oropendolas. Evidently, they recognized her as an enemy 

 and united in communal defence without regard to the nest threatened. I 

 saw a female from group 1 fly to the protection of a nest in group 3. Cassidix 

 retreated to another part of the tree where she was not molested. Within 10 

 minutes she made another attempt but was again defeated. Even two Legatus 

 seemed to recognize this visitor as undesirable and with fluttering wings flew 

 excitedly about her. At last she left the tree, a solitary outcast, followed by 

 half a dozen oropendolas to the boundary of their territory. 



Several entries describe the aggressiveness of Cassidix. Thus, 

 February 15, 1926, at 10.37 a. m. : " Cassidix tries to enter a nest 

 in group 2 but is mobbed and driven off; she fights back" and at 

 10.50 the entry reads : " Cassidix tries to enter group 3, is driven off 

 by Zarhynchus; fights them in the air; Legatus joins in the attack 

 as Cassidix is routed." And on February 25, 1927, at noon : " Cas- 

 sidix enters two nests, staying 15 to 30 seconds in each. Two Zar- 

 hynchus^ and both Legatus drive her off repeatedly, but she fights 

 them as though she were defending her own nest." 



A curious performance is recorded at 8.34 a. m. on February 13, 

 1927, when my notes read: "A female Cassidix displays before or 

 addresses a female Zarhynchus on a new nest at the left of No. 5, 



