Coloniality in the yellow-rumped cacique as a defense against nest predators

Individuals of the colonial Yellow-rumped Cacique (Cacicus cela) in Amazonian Peru can defend their nests against predators in three ways. First, by nesting on islandsand around wasp nests, caciques are safe from arboreal mammals such as primates, whichdestroy many more-accessible colonies. Caimans and otters that live in lakes also protectisland colonies from snakes, which are vulnerable when crossing open water. Second, byclustering nests together and mobbing as a group, caciques can deter many avian predators,which take spatially isolated nests in small colonies.

SCOTT K. ROBINSON, The Auk 102: 506-519