The Cerulean Warbler (Setophaga cerulea) is a species of conservation need, with declines linked in part to forest habitat loss on its breeding grounds. Active management of forests benefit the Cerulean Warbler by creating the complex structural conditions preferred by the species, but further research is needed to determine optimal silvicultural strategies. We quantified and compared the broad-scale influence of timber harvests within central Appalachian hardwood forests on estimated abundance and territory density of Cerulean Warblers. We conducted point counts at seven study areas across three states within the central Appalachian region (West Virginia [n = 4], Kentucky [n = 1], Virginia [n = 2]) and territory mapping at two of the study areas in West Virginia, pre-and post-harvest, for up to five breeding seasons from 2013 to 2017. Our primary objective was to relate change in abundance to topographic and vegetation metrics to evaluate the effectiveness of current Cerulean Warbler habitat management guidelines. We used single-species hierarchical (N-mixture) models to estimate abundance while accounting for detection biases. Pre-harvest mean basal area among study areas was 29.3 m 2 / ha. Harvesting reduced mean basal area among study areas by 40% (mean 17.2 m 2 /ha) at harvest interior and harvest edge points. Territory density increased 100% (P = 0.003) from pre-harvest to two years post-harvest. Cerulean Warbler abundance increased with increasing percentage of basal area that comprised tree species preferred for foraging and nesting (i.e., white oak species, sugar maple [Acer saccharum], hickories) or of large diameter trees (≥40.6 cm diameter at breast height). Positive population growth was predicted to occur where these vegetation metrics were > 50% of residual basal area. Post-harvest abundance at harvest interior points was greater than at reference points and when accounting for years-post-harvest in modeling abundance, Cerulean Warbler abundance increased at harvest interior and reference points two years post-harvest and subsequently decreased three years post-harvest. Modeled abundance remained the same at harvest edge points. Increases in abundance and territory density were greater in stands with low pre-harvest densities (< 2 birds/ point or < 0.40 territory/ha) of Cerulean Warblers, whereas populations within stands with higher densities preharvest had minimal changes in abundance and territory density. Overall, our results indicate that harvests based on the Cerulean Warbler Management Guidelines for Enhancing Breeding Habitat in Appalachian Hardwood Forests, at all available slope positions and aspects where pre-harvest densities are < 0.40 territory/ ha, may provide breeding habitat for Cerulean Warblers for at least two years post-harvest in the central Appalachian region.

In this study, I assessed the response of Cerulean Warblers (Setophaga cerulea) and 5 additional songbird species to timber harvests prescribed through operational silviculture. The research took place in relatively contiguous mature deciduous forests in 4 states in the central Appalachian region-Kentucky, Pennsylvania, Virginia, and West Virginia, USA. For the first part of the study, I collected Cerulean Warbler abundance and territory data through point counts and territory mapping, respectively. I used the point count data to model Cerulean Warbler abundance pre-and post-harvest at 5 study areas (Kentucky [n=1], Virginia [n=2], West Virginia [n=2]) and post-harvest at an additional 2 study areas (West Virginia [n=2]). I analyzed territory data from 2 of the 4 study areas in West Virginia. The primary objective was to determine Cerulean Warbler response to timber harvests, implemented based on the Management Guidelines for Enhancing Cerulean Warbler Breeding Habitat in Appalachian Hardwood Forests ("Guidelines"), published in 2013, but covering a broader range of topographic conditions than those described in the Guidelines. The harvests at my study areas encompassed all available slope positions (i.e., lower to ridge) and aspects (i.e., Beers aspects 0-2). Two of my study areas were within the Ridge and Valley physiographic region, not included in the original study. I used 3 point types-harvest interior, harvest edge, and reference-to assess Cerulean Warbler change in abundance pre-and post-harvest and by years-post-harvest. I used dynamic, open population N-mixture models with point count data from the 5 study areas sampled pre-and post-harvest to estimate modeled abundance and population growth and change in abundance pre-to post-harvest, while accounting for detection bias. Using only the postharvest data from these 5 study areas and the count data from the 2 study areas sampled only post-harvest, I used static N-mixture models to estimate modeled abundance and change in abundance among years-post-harvest. The primary results of this analysis indicated that point type, basal area of their preferred tree species, and basal area of large diameter trees were the most important drivers of Cerulean Warbler abundance. Models including slope position and Beers aspect had limited support for the data, which is important in comparing my findings to the Guidelines in which harvests were implemented within Cerulean Warbler preferred habitat characteristics of north-to northeast-facing aspects and upper slopes and ridgelines. Territory density increased 100% between pre-harvest and 2 years post-harvest. The greatest increases in abundance and territory density occurred where pre-harvest numbers were low. For the second part of my study, I used logistic regression and resource selection functions to assess male Cerulean Warbler territory habitat selection with matched usedavailable habitat data. I used vegetation points at male Cerulean Warbler singing locations as "used" locations, which I delineated from detections ...