Bachman's Sparrow (Peucaea aestivalis) is listed as a species of conservation concern throughout its range and therefore an important candidate for demographic studies. We estimated probabilities of males' annual survival by monitoring a large color-marked population for 4 years by using a combination of (1) mark-resighting within a primary study area and (2) surveys outside the primary area to document emigration. We used multi-strata models to assess probabilities of survival, detection, and movement between the primary study area and the surrounding landscape. In the top models included in our confidence set, probabilities of annual survival were ≥0.68. Probabilities of detection and dispersal varied among the top models but averaged ≥0.86 and ≤0.14, respectively, for individuals in the primary study area. We used a survival probability of 0.68 in combination with published information on the species' productivity to construct a two-stage Leslie matrix. Survival of adult males had the greatest proportional influence on population projections (elasticity = 0.52), while survival of juveniles and annual productivity had equal influence (elasticities = 0.24). Our results suggest that off-plot surveys and multistrata models provide an efficient method for estimating probabilities of survival of Bachman's Sparrow.
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1 November 2010
Estimating Probabilities of Survival of Male Bachman's Sparrows from Plot-Based, Mark-Resighting, Off-Plot Surveys and Multi-Strata Models
James A. Cox,
Clark D. Jones
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The Condor
Vol. 112 • No. 4
November 2010
Vol. 112 • No. 4
November 2010
Bachman's sparrow
detection
elasticity
emigration
multi-strata model
Peucaea aestivalis
survival