Inter-individual variation in the migratory behaviour of a generalist seabird, the herring gull (Larus smithsoniansus), from the Canadian Arctic

Abstract

The Arctic is warming three times faster than the rest of the globe, causing rapid transformational changes in Arctic ecosystems. As these changes increase, understanding seabird movements will be important for predicting how they respond to climate change, and thus how we plan for conservation. Moreover, as most Arctic-breeding seabirds only spend the breeding season in the Arctic, climate change may also affect them through habitat changes in their non-breeding range. We used Global Location Sensors (GLS) to provide new insights on the movement of Arctic-breeding herring gulls (Larus smithsoniansus) in North America. We tracked gulls that wintered in the Gulf of Mexico (n = 7) or the Great Lakes (n = 1), and found that migratory routes and stopover sites varied between individuals, and between southbound and northbound migration. This inter-individual variation suggests that herring gulls, as a generalist species, can make use of an array of regions during migration, but may be more susceptible to climate change impacts in their overwintering locations than during migration. However, due to our limited sample size, future, multi-year studies are recommended to better understand the impacts of climate change on this Arctic-breeding seabird.

Habitat Selection and Specialisation of Herring Gulls During the Non-breeding Season

“…The remaining individuals moved considerably further (up to 185 km). These migration distances were similar, or slightly shorter, to those estimated for herring gulls in the Netherlands based on ringing recoveries (Camphuysen et al, 2011), and considerably shorter than observed for American herring gulls (Larus smithsoniansus) breeding in northeastern North America (Anderson et al, 2019;Baak et al, 2021), possibly reflecting the mild oceanic climate of coastal Western Europe compared to northeastern North America.…”

Migration, breeding location, and seascape shape seabird assemblages in the northern Gulf of Mexico

“…The structure of these assemblages demonstrates that, from a conservation perspective, environmental and anthropogenic stressors in the northern Gulf can have effects that extend across much of the north-south and eastwest footprint of the Atlantic basin. As the understanding of the behavior of seabirds occurring in the nGoM increases through tracking (e.g., [62][63][64][65]), the connectivity of the nGoM to other regions will be revealed with increasing detail.…”

Seabird vulnerability to oil: Exposure potential, sensitivity, and uncertainty in the northern Gulf of Mexico

“…increasing as the number of seasons with an occurrence increase (King and Sanger, 1979). Interannual variation in environmental conditions can impact seabird distributions, altering their exposure to threats (Baak et al, 2021;Bi et al, 2021). Therefore, seasonal occurrence can capture interannual differences in occurrence, whereas describing broad-scale distribution patterns (e.g., residency, described below) is not sensitive to this variation.…”

“…Uncertainty in residency could be reduced by increasing the understanding of seabird movements across their annual cycle, including the degree of individual and interannual variation in movement patterns. Lagrangian methods, such as individualbased tracking, can be used to better understand variation in migration patterns (Baak et al, 2021), habitat use (Jodice et al, 2015;McCloskey et al, 2018;Phillips et al, 2018), and overlap with threats (Lamb et al, 2018;Isaksson et al, 2021). Tracking has identified previously unknown breeding areas (Kanai et al, 2002) and demonstrated links with distant colonies with seabirds using the nGoM (Montevecchi et al, 2012).…”