Date of Award
Master of Science in Biological and Environmental Sciences (MSBES)
Ecology and Ecosystem Sciences
Natural Resources Science
Scott R. McWilliams
Early successional forests are a rare and declining forest type in the Northeastern U.S., and active management is required in order to maintain this habitat for the many declining bird populations that inhabit these areas. Studies on the movements, spatial ecology, and habitat selection of declining species of interest within newly created habitats offer opportunities to assess the success of management, and inform future management decisions and practices. Yet the impact of management may be limited by the placement of newly formed habitat within a larger landscape context. I investigated the impact of landscape and management context on the spatial ecology of American woodcock (Scolopax minor) and Eastern towhee (Pipilo erythrophthalmus) within managed early successional forests in the state of Rhode Island. First, I conducted a reciprocal transplant experiment to test if American woodcock select breeding grounds based on the perceived quality of the surrounding landscape. Second, I investigated the post-fledging and post-breeding ecology of Eastern towhees, a declining early successional forest songbird, in different landscapes managed and maintained for woodcock to test the efficacy of using woodcock as an umbrella species.
I experimentally relocated male woodcock between two types of landscapes that differed in forest composition and relative likelihood of use. Second-year male woodcock that were relocated from high-likelihood of use landscapes into low-likelihood of use landscapes during the breeding season almost always returned to their original high-likelihood landscape of capture (71%), whereas second-year male woodcock that were relocated from low- likelihood of use landscapes into high-likelihood of use landscapes (8%) seldom returned to their original low-likelihood landscapes of capture. The results from this experiment provide strong evidence that male woodcock can assess landscape-level differences in habitat, and will then settle and attempt to attract a mate(s) based on key landscape features identified by a resource selection function developed for woodcock.
I tracked the movements and post-fledging behaviors of adult Eastern towhees in areas that were initially managed for woodcock. Adult towhees in two woodcock-sized landscapes that differed in forest composition and likelihood of woodcock use averaged similar home range sizes during the post-fledging period (3.09 ± 0.43 ha, and 2.37 ± 0.49 ha, respectively), and the different landscapes had no impact on the number of young that adult birds were able to raise to independence. However, there were differences in the maximum distances adults travelled during the independence stage between the two woodcock landscapes. While there is some evidence that the forest composition of the surrounding landscapes may impact these post-breeding movements, these movements coincided with the abrupt behavioral shift of adults from caring for dependent young, to being largely independent of young and thus focused more on personal maintenance. Given that towhees successfully raised young in areas managed for woodcock in different landscape contexts, woodcock can serve as an effective umbrella species for towhees and other generalist-young forest songbirds.
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Brenner, Stephen J., "Early Successional Forest Birds and the Effects of Habitat Management in Different Landscapes" (2018). Open Access Master's Theses. Paper 1233.