204 BROOKLYN INSTITUTE MUSEUM. SCIENCE BULLETIN 2. 6. 
Cacicus cela (Linnaeus). 
Pants Ccln Linnaeus, Syst. Nat. ed. lo. 1758. p. 191.' 
CassicHS pcrsicus Berlepsch, Ibis. 1884, p. 433 (Angostura and Rio 
Apure). 
Cassiciis albirosfris Berlepsch & Hartert, Novit. Zool. IX. 1902. p. 30. 
Native name Arreiidajo. 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 abundant 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 
liliacca 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. Aly 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 colooies 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 popidation. the 
wasp nests were cither 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 comiunn 
Baltimore Oriole. As the rains begin to come, after the eggs have been 
laid, and often the young hatchcil, the top entrance is gradually rooted 
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. 
