386 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 



of their homes offsets the advantages of colonial nesting with its 

 implied absence of marked sexual and territorial jealousy and in- 

 creased protection through the community interests that make the 

 enemy of one the enemy of all. 



Zarhynchus can not lay the slightest claim to the possession of a 

 protectively hued plumage. In color, size, and habit, during the 

 most critical period of its annual cycle, it is highly self-advertising. 

 Its safety depends on that constant vigilance which keeps it ever 

 on the alert and on the instant, unquestioned obedience to the alarm 

 note that prompts it to dive headlong into the dense vegetation 

 from which it is never far distant. 



POSTSCRIPT 



The day that this paper was completed I received word from Mr, James 

 Zetek, resident custodian of Barro Colorado, that the sand-box tree in which 

 the oropendolas nested was blown down by a severe windstorm on August 28, 

 1928. Evidently, lilve its predecessor, this tree, as a member of a forest com- 

 munity, had not developed sufficient hold upon the ground to stand alone. 



I had hoped that this contribution to our knowledge of the nesting habits 

 of Zarhynclius would form the opening chapters of a history that would in- 

 crease in interest as added data enabled us to view the present in the light of 

 the past. But so far as the sand-box colony is concerned I can now write only 

 finis, 



SECOND POSTSCRIPT 



On March 8, 1930, what for various reasons we believe to be the laboratory 

 colony of oropendolas was found in a large almendro (Coumaronna panamensis) 

 situated about a mile from the laboratory near No. 14 on the Shannon Trail. 



On January 8, 1931, 17 oropendolas, including 4 males, were observed in this 

 tree. They had evidently begun to build on January 6 or 7. These dates are 

 so near those records for the laboratory colony (Jan. 8; Jan. 8; Jan. 2; antea, 

 p. 352) that they further emphasize the seasonal regularity of the breeding of 

 these birds on Barro Colorado and, at the same time, confirm our belief that 

 the laboratory colony moved to the almendro. 



