Research Projects

Physiological Readiness for Reproduction in Migratory Birds Transitioning from Winter to Breeding

Field Site - Middleton Island, Alaska, USA

In migratory species, the period preceding reproduction (prebreeding stage) is particularly critical for individuals to transition from the non-breeding stage to breeding, greatly influencing their phenology and success. In this project, we use an experimental approach to study the carry-over effects across the annual cycle of black-legged kittiwakes (Rissa tridactyla).  We manipulate the energy expenditure of free-ranging individuals during the breeding season through two methods: ad libitum feeding (increasing energy gain and reducing energy costs) and flight feather clipping (increasing energy costs associated with flying).

The study takes place on Middleton Island, located in the Gulf of Alaska, a unique site featuring an old Cold War radar tower repurposed as a seabird colony and monitored by the Institute for Seabird Research and Conservation (ISRC), offering exceptional access to breeding seabirds. We deploy solar geolocators to track non-breeding individuals and record their wintering locations and behaviour. Upon their return to the colony the following spring, we recapture the birds to assess their nutritional condition during the prebreeding stage. Blood samples are collected to evaluate their physiological readiness for reproduction through hormone challenges.

Ultimately, we aim to identify the key factors that influence breeding readiness in seabirds, including environmental and feeding conditions at the breeding site during the prebreeding stage, the nutritional condition and quality of individuals or their partners, the timing of arrival at the breeding site, and conditions experienced during either winter or the previous breeding season.

Carry-over effects across the annual cycle of an Arctic-nesting seabird

Field Site - Svalbard, Norway

Migratory animals follow a tight schedule to track seasonal changes across time and space, adjusting their energy requirements in response to fluctuations in resource availability. Decisions made by individuals during one season can lead to carry-over effects that influence their success in subsequent seasons. We take an integrative approach to study the processes behind these carry-over effects, focusing on 1) migratory behaviour, 2) energy expenditure, 3) exposure to contaminants and 4) stress physiology.

We conducted this research in Svalbard, home to the northernmost breeding population of black-legged kittiwakes (Rissa tridactyla). For two decades, the Centre d'Études Biologiques de Chizé (CNRS, France) and the Norwegian Polar Institute have monitored a colony in the region. Since 2008, we have tracked kittiwakes during winter as part of the SEATRACK initiative, providing a rare long-term record of their non-breeding movements.

We combined this long-term tracking dataset with hormonal and contaminant analyses, breeding monitoring, and experimental manipulations of reproductive effort to uncover the underlying mechanisms behind carry-over effects.

Migratory species are vital links between ecosystems, connecting regions and habitats as they travel across vast distances during their annual cycles. These movements, and the spatial distribution of migratory species, are shaped by a combination of biotic factors, such as food availability and predation, and abiotic factors, including climate and geography, acting on both the breeding and non-breeding stages. At the Bylot Island Field Station in the Canadian Arctic, we investigate these dynamics by studying how migratory shorebirds connect the Arctic tundra to regions as distant as South America, Europe, and Africa.

Nest predation is a significant demographic challenge for these ground-nesting species. To investigate how species-specific differences in predation risks influence large-scale distribution patterns, we conducted artificial nest experiments and demographic monitoring.

Arctic-breeding shorebirds are also remarkable long-distance migrants whose routes have evolved to overcome major ecological barriers. We tracked species like the Ringed Plover ᖁᓪᓕᖁᓕᐊᕐᔪᒃᖁᓪᓕᖁᓕᐊᖅ (Charadrius hiaticula) using solar geolocators to study the impact of ecological barriers (e.g., oceans, ice caps) and dominant wind patterns on their migratory routes.