204 BROOKLYN INSTITUTE MUSEUM. SCIENCE BULLETIN 2. 6. 



Cacicus cela (Linnaeus). 

 Parns Cela Linnaeus, Syst. Nat. ed. lO. 1758. p. 191. ^ 



Cassiciis persicus Berlepsch, Ibis. 1884, p. 433 (Angostura and Rio 



Apure). 

 Cassicits albirostris Berlepsch & Hartert, Novit. Zool. IX. 1902. p. 30. 



Native name Arrendajo. A common bird all along the lower 

 stretches of the river including the delta region, and along the middle 

 .stretches, as far as the mouth of the Meta. Also abvmdant along 

 the lower Caura River. Nesting in colonies and frequenting the nesting- 

 trees throughout the year. The colonies vary in size from half 

 a dozen to seventy-five or eighty nests placed close beside one 

 another and at heights above the ground of from 7.6 m. to 30 m. 

 No single species of tree seems to be preferred; but the tree selected 

 and the height from the ground appears to be determined by the 

 presence of the nest of some species of wasp (most frequently Polybia 

 liliacea Fabricius), or not uncommonly a nest of stingless bees which 

 forms the centre about which the bird village is built. The most cordial 

 good-fellowship appears to exist between the birds and their insect neigh- 

 bors. My observations have not indicated any direct relationship between 

 the size of the bird and insect colonies. However, when through accident 

 or natural causes the wasp nests are destroyed or abandoned the sur- 

 rounding bird colonies seem to dwindle in size and are finally also aban- 

 doned. A number of colonies of Arrendajo that I noted when on the 

 Orinoco in 1897 and 1898, were still in existence in 1905, some flourish- 

 ing, others in decadence and some abandoned. And in every instance 

 where a colony had been abandoned or had decreased in population, the 

 wasp nests were either broken down or had been abandoned. 



Nesting begins toward the end of the dry season, in April, and 

 continues until June ; and what appears to be an intelligent adaptation 

 to circumstances is seen in the finishing of the nests. During the early 

 part of the breeding season, before the rains have begun to come, the 

 nests are almost all open from the top as in the case of our common 

 Baltimore Oriole. As the rains begin to come, after the eggs have been 

 laid, and often the young hatched, the top entrance is gradually roofed 

 over and the nest entrance becomes a bent tube with the opening down- 

 ward. The nests are purse-shaped bags tightly woven from long, tough, 

 narrow-bladed marsh grasses. Some are provided with an inner lining 



'See Hellmayr. Novit. Zool. XIII. 1906. p. 20. 



