An estimate of juvenile survival in black-capped vireos and its implications to source-sink analyses of songbirds
This article is part of a larger document. View the larger document here.Abstract
An indirect estimate of juvenile survival was derived for a closed, small, population of Black-capped Vireos (Vireo atricapillus) in the Wichita Mountains, Oklahoma monitored since 1987. I used seasonal fecundities of vireos in years when the population was stable in the formula for intrinsic growth rate to solve for juvenile survival. The derived probability of juvenile survival to breeding was 0.40-0.57, more than two-thirds the annual adult-female survival. This result parallels the observations of Nolan (1978) for Prairie Warblers (Dendroica discolor). It suggests that the conservative rule-of-thumb estimate for juvenile survival (i.e., half that of adult females) used in assessing source-sink relations among different groups of songbirds contributes to underestimating their intrinsic growth rates. This, in turn, may alter interpretations of source-sink dynamics for songbirds, and consequent management recommendations derived from such assessments.