Behavior & the Environment
Seabirds are a large and diverse group of marine predators that present an opportunity to compare the interacting effects of the environment, resource competition, and intrinsic constraints, such as sex, age and molt on foraging strategies. In general, there is great diversity in how different seabird species find and catch food, and research conducted in our lab has investigated foraging strategies in species that are the deepest avian divers as well as species that feed exclusively at the surface but travel vast distances across ocean basins in search of food.
Foraging strategies don’t just differ between species, but given the high levels of intraspecific competition at seabird breeding colonies, they often vary within species as well. Many seabirds have age and sex specific strategies, and these sometimes vary in different environments. Additionally, seabirds can be very long-lived – many species have lifespans similar to humans – and so present a unique opportunity to investigate the effects learning, memory and experience on foraging behavior. More and more research indicates that seabirds often show consistency in foraging behavior as well as foraging habitat and post-breeding molting grounds, which has large implications on seabird conservation, since different groups within the population might be exposed to different, and consistent, risks.
Seabirds traverse large areas of the ocean during foraging and migration. These movements make them excellent samplers of the marine environment as they search for food like fish and squid. Because contaminants are ubiquitous in today’s world, using seabirds to sample contaminants in the ocean can help us assess contaminants in top predators like seabirds and in marine foodwebs. We use seabirds’ foraging ecology to study the distribution of contaminants in the tropical and temperate oceans.
Breeding seabirds are constrained by both time and distance while foraging at sea because they must return to nesting grounds to deliver meals to their chicks. Efficient foraging strategies are thus essential for minimizing metabolic (energy) costs to the adult and maximizing energy delivery to chicks. When changes occur in the accessibility and predictability of food resources, seabirds may expend more energy searching for food. In addition, changes in environmental characteristics, such as increasing wind speeds, can alter energy expenditure during foraging trips. Seabirds may adapt behaviorally within their lifetime to locate food, but rapidly forced changes during already constrained chick rearing periods may cause underlying physiological stress that ultimately reduces fitness. Measuring physiological parameters (such as metabolic activity and stress hormone levels) in relation to different foraging patterns allows us to better predict the adaptability of seabirds to environmental changes.