Landscape-Dependent Effects of European Starlings (Sturnus Vulgaris) on Native Breeding Birds in Kansas

Invasive species are a leading driver of biodiversity change, yet their effects often vary across habitats and species. The European Starling (Sturnus vulgaris), introduced to North America in the late 19th century, is an aggressive cavity-nesting bird that has expanded widely across Kansas. We evaluated the influence of European Starling presence on five native cavity-nesting and open-cup breeding birds - Carolina Chickadee (Poecile carolinensis), Eastern Bluebird (Sialia sialis), Black-capped Chickadee (Poecile atricapillus), Tree Swallow (Tachycineta bicolor), and House Wren (Troglodytes aedon) - using eBird checklists collected statewide during breeding seasons 2015 - 2024. Using generalized linear mixed models, we quantified species-specific associations with European Starling presence across grassland, forest, agriculture, and urban habitats. We found expected richness of native species was lower on checklists where European Starlings were present, particularly in urban and forest habitats, whereas grasslands and agriculture exhibited relatively stable expected richness. The magnitude and direction of these associations varied among species, reflecting differences in nesting behavior, habitat preference, and ecological niche overlap. These findings suggest that associations between European Starlings and native breeding bird communities are habitat-dependent and species-specific, with human-altered landscapes and forests showing the strongest negative associations with native bird richness. Our work highlights the importance of integrating habitat context and species traits in assessing invasive species impacts. Our work will inform management strategies aimed at mitigating competitive pressures in urban and forests areas while conserving resilient native bird populations in natural habitats.