Proximate mechanisms behind carry-over effects mediated by key reproductive hormones in migratory seabirds

Long-lived animals, including seabirds, must balance investment in current reproduction with investment towards survival and future reproduction to maximize their lifetime fitness. Breeding is a critical stage in birds annual life cycle and requires high energy expenditure. Increased reproductive effort in the current year can therefore lead to costs that will have downstream consequences into subsequent life stages, including migration and overwintering or the next breeding season. Such carry-over effects can have strong impacts on fitness and population dynamics, but mechanisms underlying such seasonal interactions remain unclear. I monitored breeding and migration of an Arctic-breeding seabird, the black-legged kittiwake (Rissa tridactyla), and captured individuals at their return to the colony site to assess the physiological state and reproductive preparedness of individuals as they transition into the next breeding season. We used hormone challenges and collected blood samples to assess levels of the ‘stress hormone’ corticosterone and key reproductive hormones: luteinizing, estrogen and testosterone. Hormones, and endocrine processes, are the mediators linking the individual perception of its environment and its reproductive decisions and success, driving the ability of individuals to cope with environmental stressors.

Faculty Supervisor:

Kyle Elliott

Student:

Partner:

Centre d'Etudes Biologiques de Chizé

Discipline:

Life Sciences

Sector:

Life Sciences (not health); Environmental Science and Technology

University:

McGill University

Program: