Madeline A. Dykstra’s research while affiliated with Calvin University and other places

Black-capped chickadees (Poecile atricapillus) and other species that feed at bird feeders balance the benefit of easy foraging with the added risk of predation. Individual birds respond differently to risky situations, and these differences have been attributed to the birds’ personalities, which researchers commonly assess with an “open-field” behavioral assay. However, these behavioral assays in birds have not been compared to behavior in the wild in the context of foraging in the presence of a predator (i.e., risk-taking behavior). We color-banded chickadees in a wild population and conducted behavioral assays in the field. We later used foraging trials to investigate these color-banded individuals’ responses to a predator (Cooper’s hawk, Accipiter cooperii) model or a series of Cooper’s hawk calls. We found that foraging black-capped chickadees responded more strongly to the presence of a predator model than to predator calls. Individual birds differed in their responses, and the behavioral assays (activity and exploration) predicted individual behavior in the wild during the foraging experiments. Activity and exploration assay scores were only weakly related, suggesting these two assays represent different traits. Both highly active birds and fast explorers exhibited some reluctance to visit the feeder (either reduced number of visits or greater latency to visit) when the predator model was present, a relationship that was somewhat unexpected. Our results suggest that standard behavioral assays predict behavior in the wild, but care should be taken when generalizing among species and studies.

The south Florida subspecies of the Red-shouldered Hawk (Buteo lineatus extimus) is distinctly paler and smaller than other subspecies, reproduces at a lower rate, and can occupy very different habitats such as open marshes and grasslands with only scattered trees. We evaluated population differentiation between the south Florida population of Red-shouldered Hawks and two populations of eastern Red-shouldered Hawks (B. l. lineatus) in suburban (Cincinnati) and rural (Hocking Hills) environments in southern Ohio. Based on analysis of 11 microsatellite loci, we found significant genetic differentiation between the south Florida and eastern populations (FST = 0.077–0.097), as well as significant differentiation between the two populations of the eastern subspecies (FST = 0.047). Standardized genetic distance principal components analysis indicated two clusters, with individuals from the two Ohio populations forming a single cluster and those from Florida forming a second cluster. The substantial differences between the south Florida and other subspecies suggest this population warrants attention and possibly management as a distinct conservation unit, particularly in light of possible threats including habitat loss and rodenticide exposure. La subespecie del sur de Florida Buteo lineatus extimus es claramente más pálida y más pequeña que otras subespecies, se reproduce a un ritmo menor y puede ocupar hábitats muy diferentes, como marismas abiertas y pastizales con solo árboles dispersos. Evaluamos la diferenciación poblacional entre la población de B. l. extimus del sur de Florida y dos poblaciones orientales de B. l. lineatus de ambientes suburbanos (Cincinnati) y rurales (Hocking Hills) en el sur de Ohio. Con base en el análisis de 11 loci de microsatélites, encontramos una diferenciación genética significativa entre las poblaciones del sur de Florida y las orientales (FST = 0.077–0.097), así como una diferenciación significativa entre las dos poblaciones de la subespecie oriental (FST = 0.047). El análisis estandarizado de componentes principales de la distancia genética mostró dos grupos, con individuos de las dos poblaciones de Ohio formando un solo grupo y aquellos de Florida formando un segundo grupo. Las diferencias sustanciales entre el sur de Florida y otras subespecies sugieren que esta población merece atención y posiblemente manejo como una unidad de conservación distinta, particularmente a la luz de las posibles amenazas que incluyen la pérdida de hábitat y la exposición a rodenticidas. [Traducción del equipo editorial]