Kate Slankard

Barn Owls (Tyto alba) are a species of conservation interest, but management of nesting populations can require significant effort. To focus management activities, we conducted analyses of statewide survey data collected for Barn Owl nests (n = 515) and roosts (n = 145) in Kentucky, USA, from 2010–2022. Nest and roost sites included natural (e.g., trees, rock shelters) and human-made (e.g., barns, attics, hunting blinds, silos, etc.) structures and nest boxes (n = 270) installed on various substrates. Using data related to land cover, agricultural features, and other habitat-related variables, we examined factors influencing Barn Owl site occupancy by creating habitat suitability models. Additionally, we assessed changes in nest box occupancy over time and the factors that influenced nest box occupancy. The Shannon habitat diversity index and number of buildings within 75 m were the most important variables for habitat suitability throughout the study area, though the proportion of hay/pasture/grassland within 625 m and distance to an area intensively managed for Barn Owls were important regionally. Barn Owl nest box occupancy increased over the course of our study, likely due to management efforts. Owls were more likely to occupy nest boxes if they were installed on tall feed silos, retired utility poles, or barns. Moreover, nest boxes installed at sites where we observed owl pairs (prior to installation) were more likely to become occupied and used sooner than nest boxes installed opportunistically. Future management should focus on installing nest boxes for known pairs, on unused feed silos, on retired utility poles on reclaimed surface mines, and near areas intensively managed for the species.

While native grass and shrub restoration is often promoted for bird conservation, evaluations are necessary to understand the effects of habitat change on songbird vital rates and migratory stopover use. We evaluated the effects of native vegetation restoration on the species richness, productivity, and capture rate of breeding and fall migrating songbirds at the Shaker Village of Pleasant Hill, in central Kentucky, USA. From 2009 to 2022, we conducted constant effort mist netting, resulting in 8418 captures of 110 bird species. In 2012–2013, we implemented management in the study area, which began as an old field, to restore native grasses, forbs, and shrubs. Effects on the vital rates of breeding species included higher Spizella pusilla (field sparrow) and Spinus tristis (American goldfinch) productivity post restoration. Restoration of native vegetation also led to significantly higher fall capture rates for pooled cohorts of both long-distance and medium-distance migrants. Our results demonstrate that the restoration and management of native vegetation can enhance stopover habitats for fall migrating songbirds including neotropical migrants and the field sparrow, a common bird in steep decline. We recommend prioritizing areas for native grass and shrub restoration that initially lack structural heterogeneity (a well-developed grass component with diverse forbs and interspersed shrubs).

Raptor nests on human‐built structures represent a significant source of conflict, as they can result in bird mortality, fires, or power outages due to falling nest materials or animals connecting with energized conductors. Power companies typically try to mitigate these conflicts to avoid service disruptions. Performing mitigation measures across all potentially problematic power infrastructure is generally not a practical solution given logistical, time, or budgetary constraints. Therefore, there is a need for quantitative, landscape‐scale tools to identify conflict risk and prioritize mitigation. We examined the influence of habitat and transmission infrastructure distribution on the potential risk of osprey (Pandion haliaetus) nesting‐infrastructure conflict in the Tennessee Valley Authority (TVA) power service area within Tennessee, Alabama, Georgia, Kentucky, Mississippi, North Carolina, and Virginia, USA, using osprey nesting and conflict records from 1990–2020. We modeled risk using a 3‐stage approach, which intersected a nesting habitat suitability model and density of infrastructure to evaluate the potential risk of conflict. Habitat suitability was greater on or near open water and closer to developed areas. Transmission line density was low (0.14 ± 0.29 lines/km²) and heterogenous across the service area with more lines within urban centers and near power facilities. Integrating habitat suitability and transmission infrastructure information revealed that very low and low‐risk areas comprised 99% of the service area. Less than 1% comprised 1,113.7 km² of moderate and 82.2 km² of high or very high risk, mostly concentrated along major rivers and lakes, and around urban centers. Risk was more prevalent in the northeastern portion of the service area. This work presents a top‐down approach to mitigating osprey–power infrastructure conflict, which allows for the prioritization of mitigation actions and can facilitate long‐term coexistence with this protected species.

Kentucky's breeding Haliaeetus leucocephalus (Bald Eagle) population began recovering in 1986, with a single nest, and has since expanded from the state's western portion to the central and eastern regions. We used aerial survey data to describe the spatiotemporal distribution of Bald Eagle nests in Kentucky, to examine changes in nest-site selection relative to natural and anthropogenic features, and to create a nesting-habitat suitability model. Our results highlight increased nesting near developed areas in recent years. Although nests in these areas productively contribute to populations, we note some considerations of increased risks associated with nesting in developed areas. We also provide predictions of available nesting areas and data to direct the future monitoring and management of Bald Eagles in Kentucky.

The Cerulean Warbler (Setophaga cerulea) is a declining Nearctic–Neotropical migratory songbird of conservation concern. Implementing full annual cycle conservation strategies to facilitate recovery has been difficult because we know little about the migratory period or strength of migratory connectivity between North American breeding and South American nonbreeding regions. Between 2014 and 2017, we deployed geolocators on 282 males at 14 study sites throughout the species’ range to (1) evaluate the strength and pattern of connectivity between breeding and nonbreeding regions, (2) identify approximate routes and stopover regions, and (3) document migration phenology. We obtained data from 26 birds and observed moderate migratory connectivity overall but documented strong parallel migration for birds breeding in two longitudinally disparate regions. Most (14 of 15; 93%) Appalachian breeders spent the stationary nonbreeding period in the Colombian/Venezuelan Andes, whereas most (5 of 7; 71%) Ozark-breeders spent the stationary nonbreeding period in Peru/Ecuador. The majority of spring migration (62%) was spent in Central America at multiple stopover locations between Panama and southern Mexico. The 2 migratory periods were approximately equal in duration: 38 ± 2 days (SE) in fall and 42 ± 2 days (SE) in spring. Based on the observed connectivity pattern, conservation of Appalachian-breeding populations during the stationary nonbreeding period should focus on forest conservation and restoration in pre-montane/lower montane forests of Colombia and Venezuela, whereas Ozark-breeding population conservation should focus on forest conservation and restoration efforts in Ecuador and Peru. Further conservation efforts are also needed on the breeding grounds, especially for the most sharply declining populations. And finally, conservation of forests used by Cerulean Warblers during stopover periods throughout Central America and southern Mexico, in southeastern United States coastal areas, and in the Mississippi Alluvial Valley will benefit individuals from multiple breeding locations and populations. • Many bird species that migrate between North and South America are declining in population and to inform conservation strategies we must identify where vulnerable populations spend time at different points in the year. • Cerulean Warblers are declining forest songbirds that breed in eastern North America and travel annually to the tropical Andes of South America, where they spend ~ 6 months per year. • We captured and equipped Cerulean Warblers with light-level sensors (geolocators) to track their annual movements. • Birds from the east of the breeding range tended to travel to the eastern nonbreeding range in the Andes of Colombia and Venezuela and birds from the west of the breeding range tended to travel to the south-western portions of the nonbreeding range in Peru and Ecuador. • We also identified the extensive use of migratory stopover locations (rest/refueling) in Central America and southern Mexico. • Our findings are important for informing the management and conservation of this species by highlighting the importance of stopover regions and connecting specific breeding and nonbreeding regions.

Immature raptors often travel long distances and move nomadically from the time they leave their natal area to the time they are recruited into the breeding population. Emphasis on identifying the nesting and winter habitat of Bald Eagles (Haliaeetus leucocephalus) has overshadowed the need to understand the habitat and spatial use of young eagles prior to reaching maturity. We used satellite telemetry to track the movements of immature Bald Eagles hatched in western Kentucky during 2010–2016. We analyzed movement data to identify high-use areas for eagles in their first and second years during warm and cool periods. Five out of seven eagles migrated north to the Great Lakes region during their first year. Using Brownian Bridge Movement Modelling, we identified 47 noncontiguous high-use areas during the warm period and 67 during the cool period. Public lands comprised 17% of warm period high-use areas and 43% of cool period high-use areas. High-use areas were located in Illinois, Indiana, Kentucky, Arkansas and Tennessee, and were often near federally-owned dams, rivers with sandbars, or areas with abundant waterfowl. Our small sample of tracked eagles correctly identified known Bald Eagle concentration areas within the study area; thus, we infer that previously unrecognized high-use areas identified by this study are likely to be concentration areas important to the larger population. We further suggest remote sensing data, even in limited datasets, as an efficient way to identify Bald Eagle concentration areas.

Raptors, including eagles, are geographically widespread and sit atop the food chain, thereby serving an important role in maintaining ecosystem balance. After facing population declines associated with exposure to organochlorine insecticides such as dichlorodiphenyltrichloroethane (DDT), bald eagles (Haliaeetus leucocephalus) have recovered from the brink of extinction. However, both bald and golden eagles (Aquila chrysaetos) are exposed to a variety of other toxic compounds in the environment that could have population impacts. Few studies have focused on anticoagulant rodenticide (AR) exposure in eagles. Therefore, the purpose of this study was to determine the types of ARs that eagles are exposed to in the USA and better define the extent of toxicosis (i.e., fatal illness due to compound exposure). Diagnostic case records from bald and golden eagles submitted to the Southeastern Cooperative Wildlife Disease Study (University of Georgia) 2014 through 2018 were reviewed. Overall, 303 eagles were examined, and the livers from 116 bald eagles and 17 golden eagles were tested for ARs. The percentage of AR exposure (i.e., detectable levels but not associated with mortality) in eagles was high; ARs were detected in 109 (82%) eagles, including 96 (83%) bald eagles and 13 (77%) golden eagles. Anticoagulant rodenticide toxicosis was determined to be the cause of mortality in 12 (4%) of the 303 eagles examined, including 11 bald eagles and 1 golden eagle. Six different AR compounds were detected in these eagles, with brodifacoum and bromadiolone most frequently detected (81% and 25% of eagles tested, respectively). These results suggest that some ARs, most notably brodifacoum, are widespread in the environment and are commonly consumed by eagles. This highlights the need for research to understand the pathways of AR exposure in eagles, which may help inform policy and regulatory actions to mitigate AR exposure risk.