I am interested in the population biology and behavioral ecology of vertebrates (mainly birds and mammals), and the conservation biology of all taxa. I am also interested in island ecology, where islands are defined as any area of hospitable habitat that is surrounded by inhospitable space. My studies of island ecology thus include research on true oceanic islands in the Caribbean and habitat islands in urban landscapes.
I have just completed a 12 year population study of the Eastern Kingbird (Tyrannus tyrannus), a long-distance, Neotropical migrant bird. With the collaboration of many students, I (a) examined parental behavior and the dynamics of male:female interactions while rearing young, (b) assessed parentage using DNA fingerprinting, and most recently, (c) described habitat-specific population dynamics. I am currently initiating new studies to examine the population biology of forest birds living within the extensive forest park system of Portland, Oregon. This work is just beginning and will address questions ranging from the impact of domestic cats on avian nest success, to the influence of landscape structure on the dispersal dynamics and persistence of populations in isolated fragments of urban forest. I am also continuing my research on the winter ecology of Neotropical migrant birds on San Salvador, The Bahamas. My work on the island (since 1994) has led to quantitative descriptions of species-specific patterns of habitat use and population trends, and has shown that several species exhibit highly biased female sex ratios on the island, while other species with balanced sex ratios exhibit strong sexual habitat segregation. Current research is designed to answer why sexual habitat segregation occurs in these species.