Authors: M. R. Cólon, E. A. Martinez, K. Wolf-Roque, M. L. Morrison

Little information is available regarding the distribution of the endangered black-capped vireo (Vireo atricapilla) on its wintering grounds along the Pacific slope of mainland Mexico. We surveyed 62 sites from October 2011 to January 2012 to identify previously undocumented wintering locations for the blackcapped vireo. We located 66 individuals at 31 sites (47%) in seven states, including Michoacan, Guerrero, and Oaxaca, where there have been few surveys for black-capped vireos. Vireos occupied sites between 12 and 1,328 m, with slopes ≤23°. We detected vireos at 67% of dry forest and 17% of pine-oak (Pinus-Quercus) forest survey sites. Occupied locations were commonly characterized as deciduous, semideciduous, or agricultural lands and other disturbed areas. We found no evidence of latitudinal segregation in this species on its wintering grounds. These observations contribute to our understanding of the distribution and ecology of wintering black-capped vireos.