Multicolony tracking reveals the winter distribution of a pelagic seabird on an ocean basin scale

Abstract

Aim An understanding of the non‐breeding distribution and ecology of migratory species is necessary for successful conservation. Many seabirds spend the non‐breeding season far from land, and information on their distribution during this time is very limited. The black‐legged kittiwake, Rissa tridactyla, is a widespread and numerous seabird in the North Atlantic and Pacific, but breeding populations throughout the Atlantic range have declined recently. To help understand the reasons for the declines, we tracked adults from colonies throughout the Atlantic range over the non‐breeding season using light‐based geolocation. Location North Atlantic. Methods Geolocation data loggers were deployed on breeding kittiwakes from 19 colonies in 2008 and 2009 and retrieved in 2009 and 2010. Data from 236 loggers were processed and plotted using GIS. Size and composition of wintering populations were estimated using information on breeding population size. Results Most tracked birds spent the winter in the West Atlantic, between Newfoundland and the Mid‐Atlantic Ridge, including in offshore, deep‐water areas. Some birds (mainly local breeders) wintered in the North Sea and west of the British Isles. There was a large overlap in winter distributions of birds from different colonies, and colonies closer to each other showed larger overlap. We estimated that 80% of the 4.5 million adult kittiwakes in the Atlantic wintered west of the Mid‐Atlantic Ridge, with only birds from Ireland and western Britain staying mainly on the European side. Main conclusions The high degree of mixing in winter of kittiwakes breeding in various parts of the Atlantic range implies that the overall population could be sensitive to potentially deteriorating environmental conditions in the West Atlantic, e.g. owing to lack of food or pollution. Our approach to estimating the size and composition of wintering populations should contribute to improved management of birds faced with such challenges.

Seabirds and climate: knowledge, pitfalls, and opportunities

“…The use of different spatial scales is not clearly justified in all studies (e.g., Soldatini et al, 2014) and an understanding of the spatial use of marine habitat made by each species in each period of the life cycle is essential to test appropriate hypotheses on the effect of climate on seabird ecology (Frederiksen et al, 2004a;Scott et al, 2006). To that end, the improvement of technology in recent decades (e.g., Burger and Shaffer, 2008;Wakefield et al, 2009) has allowed researchers to increase their knowledge about migration routes (e.g., Guilford et al, 2009;Egevang et al, 2010), wintering areas (González-Solís et al, 2007;Frederiksen et al, 2012) and foraging areas also during reproduction (Gremillet et al, 2004;Guilford et al, 2008) and apply oceanographic indices at more appropriate temporal and spatial scales (Duffy, 1993;Weimerskirch et al, 2012).…”

Individual-level Variation and Higher-level Interpretations of Space Use in Wide-ranging Species: An Albatross Case Study of Sampling Effects

“…Commonly in multi-colony tracking studies, the size of the areas used and the degree of at-sea spatial segregation among seabird colonies are delineated by a pooled KDE from a sample of tracked individuals from each group. The size of pooled KDE 50 or 95% contours are quantified and compared, and the degree of overlap between groups is calculated (e.g., Young et al, 2009;Frederiksen et al, 2012;Thiebot et al, 2012;McFarlane Tranquilla et al, 2013;Ratcliffe et al, 2014). However, without consideration of individual variation within an available dataset, these higher-level inferences can be inadvertently misleading.…”

“…For black-legged kittiwakes (Frederiksen et al, 2012) and murres (Uria spp., McFarlane Tranquilla et al, 2013), the overwinter movements of tracked individuals have been taken to represent all of their colony members proportional to the colony's breeding population, thereby "distributing" members among specified regions of interest. Pooled KDE 50% contours generated from 15 or fewer individuals were taken to represent 11 of 16 kittiwake study colonies, and three of those colonies were represented by 5-7 tracked birds (Frederiksen et al, 2012). For example, seven birds from one colony represented the spatial distributions of c. 150,000 pairs nesting in the Newfoundland-Labrador Shelf Large Marine Ecosystem.…”

“…Defining period-specific space use can help to identify the source or severity of common or distinct threats posed at different periods in the annual cycle for a species, and for further sub-groups divided by for example age-class (e.g., Péron and Grémillet, 2013;Riotte-Lambert and Weimerskirch, 2013;Gutowsky et al, 2014a), or sex (e.g., Phillips et al, 2004;Hedd et al, 2014). At the colony level, individual-based tracking data have been used to discern period-and colony-specific space use and potential associated impacts for population dynamics for a variety of seabird species (e.g., Young et al, 2009;Catry et al, 2011;Gaston et al, 2011;Wakefield et al, 2011;Frederiksen et al, 2012;McFarlane Tranquilla et al, 2013).…”

The Dynamics of the North Atlantic Subpolar Gyre Introduces Predictability to the Breeding Success of Kittiwakes

“…Climatic changes are often proxied simply as temperature changes (Frederiksen et al, 2007b), while the physical processes responsible have largely remained elusive. The advent of geolocators has revealed that many seabird species from the NE Atlantic occupy northwestern (NW) Atlantic waters during the non-breeding period, likely due to better food availability during winter (Frederiksen et al, 2012). Processes impacting the food abundance in the NW overwintering region (Bogdanova et al, 2011) could therefore have a profound impact on several seabird populations due to "carry-over effects" on the breeding success during the following summer, and also due to the high mortality during the non-breeding season (Harris et al, 2005).…”