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Low Kirtland’s Warbler fledgling survival in Wisconsin plantations relative to Michigan plantations


Olah, Ashley et al. (2023), Low Kirtland’s Warbler fledgling survival in Wisconsin plantations relative to Michigan plantations, Dryad, Dataset,


The Kirtland’s Warbler (Setophaga kirtlandii) is a formerly endangered habitat specialist that breeds mainly in young jack pine (Pinus banksiana) forests in northern Lower Michigan, USA. The species is conservation-reliant and depends on habitat management. Management actions have primarily focused on creating jack pine plantations, but the species also breeds in red pine (Pinus resinosa) plantations in central Wisconsin, USA. However, the plantations were not intended as breeding habitat and have suboptimal pine densities. While nesting success is similar between low-density red pine plantations and optimal jack pine habitat, it is not clear if low-density red pine plantations support high fledging survival. If high-quality nesting and post-fledging habitat are not synonymous, fledgling survival and breeding population recruitment may be low. We characterized survival, habitat use, and movement patterns of dependent Kirtland’s Warbler fledglings in Wisconsin red pine plantations and compared fledgling survival between Wisconsin and Michigan. Mayfield cumulative survival estimates at 30 days post-fledging were 0.20 for Wisconsin fledglings and 0.43 to 0.78 for Michigan fledglings. Logistic exposure cumulative survival estimates for Wisconsin fledglings were 0.23 to 0.34 at 30 days post-fledging. Fledglings in Wisconsin used areas where vegetation cover and density of red and jack pine were high relative to available areas but not at greater proportions than what was available. Our findings demonstrate that red pine plantations with low pine densities were not equally suitable as nesting and post-fledging habitat, as fledgling survival rates were low. We hypothesize that habitat structure, and not particular pine species, likely contributed to reduced fledgling survival in Wisconsin. Thus, we recommend including red pine as a component in managed Kirtland’s Warbler habitat only if tree densities approach optimal levels.


These data were collected using through radio-telemetry and field vegetation sampling in Adams County, Wisconsin. Fledgling Kirtland's Warblers were radio-tagged and radio-tracked daily. Vegetation data was collected at fledgling locations and areas not used by fledglings. Fledgling survival was modeled using logistic exposure models and Mayfield survival estimation. Habitat use was modeled using logistic regression. All analyses were conducted in the R Statistical Environment to produce a manuscript accepted for publication by Ornithological Applications.


National Science Foundation, Award: DGE-1256259

National Science Foundation, Award: DGE-1747503

National Institute of Food and Agriculture, Award: WIS01590