While much of my research examines basic problems in the study of mating systems, parental investment, diet specialization, and population ecology, I often apply these results to the management of endangered or commercially valuable wildlife and threatened ecosystems. My research also makes extensive use of the development of demographic models on computers that link ecosystem or other management options to risks of extinction for threatened and endangered species. This has included models of Everglades water management and Snail Kite population viability, as well as Marbled Murrelet demography in the Pacific Northwest and sea turtle nest protection programs. I am also interested in how to allocate parks and protected areas among ecosystems, and have developed methods for making continental-scale assessments of ecosystem conservation priorities that use threatened species as indicators of threatened ecosystems. In addition, students working with me have studied metapopulation dynamics of amphibians, the effects of fragmentation on avian frugivores and forest regeneration, spatial dynamics of a white-tailed deer population, and survey methods for parrots and murrelets.
Many birds start to incubate before all eggs in their clutch have been laid.
This has puzzled ecologists for decades, because early incubation results in asynchronous hatching of young and can directly lead to the death of later-hatched chicks. Experiments have examined what pr motes hatching asynchrony, especially the role of environmental factors. Manipulations were made possible by pioneering a design for nest boxes, which has been adopted for the management of other parrots and macaws. This work in Venezuela is one of the most detailed and long-term field studies of a parrot. Over 4,000 parrotlets have been banded to study demography and social systems, and to integrate and compare demographic and genetic estimates of population viability.