Behavioral ecology, population biology, conservation, behavioral endocrinology, evolutionary ecology. Virtually all of my research is based on field studies, generally using observational methods, and often following known individuals. Much of the work in my lab has involved the integration of behavioral and demographic data from the field with physiological and genetic data from the lab. My lab is equipped for extraction and enzyme immunoassays of steroid and peptide hormones, microhistology and other assays.
My current research mainly examines risk effects, or the costs of antipredator responses by prey species. Recent research with many species has shown that direct killing constitutes only a fraction of the total limiting effect of predators on their prey. We have recently examined the responses of elk to variation in the risk of predation by wolves, including changes in behavior, group size, habitat selection, feeding ecology, and spatial distributions. We related these responses to changes in nutrition, physiology, demography and population dynamics. This work won the 2010 Carl Gustav Bernhard Medal from the Royal Swedish Academy of Sciences.
Our primary field research is now with the Zambian Carnivore Programme, headed by Dr. Matt Becker, to examine risk effects and carnivore conservation in three ecosystems (Liuwa, South Luangwa and Kafue National Parks), with several species of predators and prey. This work aims to measure variation in direct predation rates and risk effects, to identify the ecological factors that drive this variation, and provide data for the conservation and management of predators and prey. In this work, we are studying African wild dogs, lions, spotted hyenas, cheetahs and leopards, together with their primary prey, which varies among species and ecosystems, but notably includes African buffalo, giraffe, wildebeest, zebra, impala, puku, lechwe and oribi.
My students and I address these questions with a variety of methods, including behavioral observations, demographic & ecological monitoring, ground and aerial censuses, camera trapping, GPS and VHF radiotelemetry, enzyme immunoassay of fecal steroid metabolites to measure pregnancy rates and glucocorticoid stress responses, measurements of abiotic factors such as weather and soil nutrients, and assessments of diet quality by chemical, radioisotope and microhistological methods.