Demographic rates of Golden-cheeked Warblers in an urbanizing woodland preserve
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Knowledge of demographics is important in conservation planning for endangered species. We monitored the endangered Golden-cheeked Warbler (Setophaga chrysoparia) at a large, discontinuous preserve in an urbanizing landscape in central Texas, USA, to estimate survival and productivity. We estimated adult male survival using a spatial Cormack-Jolly-Seber model that separated emigration from mortality by incorporating location data from resightings. Annual male survival varied from 0.45 to 0.67 from 2010 to 2015 (posterior mean ± SD = 0.57 ± 0.06). Sixty-seven percent of resighted males moved <100 m among years, but a large minority of males moved far enough across years that dispersal should be accounted for in future survival analyses. Mean predicted seasonal productivity varied from 2.32 to 3.18 fledglings territory-1 from 2011 to 2015 (mean ± SD = 2.46 ± 0.51). Seasonal productivity was best predicted by the proportion of total woodland land cover in a 1 km radius around the annual median location, total edge density in a 1 km radius, and the standard deviation of canopy height in a 100 m radius. Seasonal productivity peaked at high proportions of total woodland cover, and decreased with increasing edge and canopy height standard deviation. Annual trends for survival and productivity were similar; that is, survival and productivity were above or below average in the same years, which could have important implications for population stability. Our estimated demographic rates are within the range of those reported from the best long-term data, from Fort Hood, Texas, and support the need for large patches of nonfragmented, mature woodlands to provide high-quality breeding habitat for this species.
Keywordsbreeding phenology dispersal behavior seasonal productivity Setophaga chrysoparia spatial CJS model survival urbanizing landscape
Reidy, Jennifer L.; Thompson, Frank R.; Connette, Grant M.; O'Donnell, Lisa. 2018. Demographic rates of Golden-cheeked Warblers in an urbanizing woodland preserve. The Condor. 120(2): 249-264. https://doi.org/10.1650/CONDOR-17-86.1.