Identifying forest-obligate birds in tropical moist cloud forest of Andean Ecuador

Abstract

Large-scale transformation of forested landscapes is a major factor in loss of biological diversity in the American tropics. Investigators examining the responses of species to deforestation rarely control for variation in the amount of forest relative to other habitats at the landscape-level. Bellavista Reserve on the western slope of the Andes in Ecuador is located between similar-sized areas of pristine, protected forest, and deforested landscapes. We used strip-transect counts and mist netting to evaluate habitat use by passerine birds in a habitat mosaic consisting of abandoned pastures, forest edges, forest fragments, and large blocks of interior tropical montane cloud forest (TMCF). During 3600 net hours, we had 1476 captures, including 346 recaptures. Of 78 species captured in mist nets, 30 had sufficient counts for Poison Rate Regression (PRR) modeling (a statistical method for comparing counts). Twelve species (40%) had capture patterns indicative of an affinity for mature TMCF, and 6 species (20%) had significantly higher counts in degraded areas (forest edge, forest fragment, and regenerating pastures) than in interior TMCF. The remaining 40% showed no significant bias in detection among habitats. Combined with strip-count data, our results suggest that about 38% of the 119 species sampled at the Bellavista Reserve occur primarily in mature TMCF, avoiding edges and early second-growth forest. Populations of these species may be vulnerable to further loss, fragmentation, and degradation of TMCF and, as such, deserve additional study and a place on lists of species of conservation concern. © 2008 Association of Field Ornithologists.