Resumen:
The Clarion Wren (Troglodytes tanneri) is a small songbird restricted to Clarion Island, an oceanic island in the Archipelago of Revillagigedo, Mexico. This species lives in open habitats throughout the island, which is 6.4 km wide by 9.7 km long (Howell & Webb 1989, Brattstrom 1990). The total population size is estimated to be 340 to 400 mature individuals (BirdLife International 2012). The International Union for the Conservation of Nature (IUCN) lists this species as �vulnerable� due to the susceptibility of the island to an invasión by small mammalian predators (e.g., mice, rats; BirdLife International 2012). Most aspects of the Clarion Wren�s Ecology and behavior � including the details of their eggs, nests, and parental behavior � are unknown or poorly known. Previous research has provided anecdotal descriptions of nests and eggs with scant details (Anthony 1898, Brattstrom & Howell 1956, del Hoyo et al. 2005). Here, we provide the first comprehensive and quantitative description of the nests, eggs, and parental behavior of this endemic and vulnerable songbird.