Ornithological Note 40
There is very little information on the breeding biology of the Rufous Wren (Cinnycerthia unirufa) and, more specifically, there appears to be no published information regarding its nest (Kroodsma & Brewer 2005). On 13 November 2014, I filmed two adults building a nest at Tapichalaca Reserve, Zamora-Chinchipe Province, southeastern Ecuador. The nest, an oval structure of dry grass, moss and twigs, was 5 m up in a tree. It measured about 15 cm across and had a lateral hole some 3·5 cm wide.
References
Kroodsma, D. & Brewer, D. (2005). Rufous Wren (Cinnycerthia unirufa). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2014). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.