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Survival estimates of bird species across altered habitats in the tropical Andes

Abstract:

The probability of long-term persistence of a population is strongly determined by adult survival rates, but estimates of survival are currently lacking for most species of birds in the tropical Andes, a global biodiversity hotspot. We calculated apparent survival rates of birds in the Ecuadorian tropical Andes using a moderately long-term (11 yr) capture–recapture dataset from three habitats that varied in how much they had been modified by human activities (native forest, introduced forest, and shrubs). We fit mark–recapture models for 28 species with habitat as a covariable. For all species, recapture rates between sampling sessions were low and varied from 0.04 for Rainbow Starfrontlets (Coeligena iris) to 0.41 for Stripe-headed Brushfinches (Arremon assimilis) when averaged across all occupied habitats. Annual survival rates varied from 0.07 for Black-crested Warblers (Margarornis squamiger) to 0.75 for Violet-throated Metaltails (Metallura baroni). We found no significant differences in survival rates either among habitats or species grouped by habitat specialization. Because we found similar survival rates in native forest and human-modified habitats, our results support those of recent studies concerning the potential value of secondary habitats for the conservation of some species of birds in the tropics. However, our conclusions are tempered by the uncertainty around the estimates of survival rates. Despite the relatively long-term nature of our study, obtaining survival estimates for bird species in this region was challenging, and either more years of study or modification of field protocols may be needed to obtain more precise survival estimates.