Short- and long-term consistency in the foraging niche of wandering albatrosses

Abstract

International audienceThe wandering albatross (Diomedea exulans) is regarded as a generalist predator, but can it be consistent in its foraging niche at an individual level? This study tested short- and long-term consistency in the foraging niche in terms of habitat use, trophic level and, by inference, prey selection. Fieldwork was carried out at Bird Island, South Georgia, in May-October 2009, during the chick-rearing period. Blood (plasma and cells) and feathers for stable isotope analyses (d13C and d15N) were sampled from 35 adults on their return from a foraging trip during which they carried stomach temperature, activity and global positioning system loggers. Results suggest short-term consistency in foraging niche in relation to both oceanic water mass and trophic level, and long-term consistency in use of habitat. Consistent differences between individuals partly reflected sex-specific habitat preferences. The proportion of consistent individuals (i.e., with a narrow foraging niche) was estimated at c. 40 % for short-term habitat and trophic level (prey) preferences and 29 % for longer-term habitat preference, suggesting this is an important characteristic of this population and potentially of pelagic seabirds in general. Foraging consistency was not related to body condition or level of breeding experience; instead, it may reduce intraspecific competition

Dietary Niche Shifts of Multiple Marine Predators under Varying Prey Availability on the Northeast Newfoundland Coast

“…Trophic discrimination factors for most species are unknown, likely because controlled dietary studies of captive animals are required. Therefore, studies often use trophic discrimination factors from closely related species (Carle et al, 2014) or averages across different taxa (e.g., Steenweg et al, 2011;Ceia et al, 2012;Lavoie et al, 2012), despite many factors contributing to variation in trophic discrimination (e.g., prey type, age, breeding status, nutritional state, sex; Bond and Jones, 2009).…”

Methods for detecting and quantifying individual specialisation in movement and foraging strategies of marine predators

“…In marine ecosystems, the ratios of stable carbon and nitrogen isotopes in consumer tissues reflect those of their prey during tissue formation in a predictable manner (Phil lips et al 2009). Carbon stable isotope ratios mainly reflect the foraging habitat or carbon source of the consumer, whereas nitrogen stable isotope ratios indicate trophic position (Bearhop et al 2000, Ceia et al 2012. Since different tissues turn over at different rates, each integrates diet information over various temporal scales , Matich et al 2011.…”

“…Since different tissues turn over at different rates, each integrates diet information over various temporal scales , Matich et al 2011. For instance, plasma retains information from a few days prior to sample collection, and red blood cells from the previous 3 to 4 wk, whereas feathers and fur represent diet during moult, since keratin is metabolically inert after synthesis , Ceia et al 2012, Barquete et al 2013. Pinniped (otariid) and sea otter Enhydra lutris vibrissae, chelonian shells, baleen plates and mammalian teeth sampled sequentially can be used to represent several years of diet information (Hobson & Sease 1998, Walker & Macko 1999, Cherel et al 2009, Vander Zanden et al 2010, Eisenmann et al 2016.…”

“…Consequently, the similarity between stable isotope ratios measured in different tissues with different turnover rates or during different periods can be used as a proxy for individual diet and habitat specialisations (Wakefield et al 2015). δ 13 C or δ 15 N are often analysed separately; however, because δ 13 C has a trophic component, the studentised residuals of the relationship between δ 13 C and δ 15 N can be included in models testing for short-and long-term consistency to control for the variability in δ 13 C that could be due to δ 15 N (Votier et al 2010, Ceia et al 2012. Alternatively, a multivariate model which allows direct modelling of the covariance/correlation between these traits can be used to control for the variability in δ 13 C due to that in δ 15 N; however, this approach, to our knowledge, has not been used in the marine predator literature to date.…”

From Ice to Penguins: The Role of Mathematics in Antarctic Research

“…were similar to those from analysis of stomach contents, showing the usefulness of 13! these models for future research (Ceia et al 2012). 14!…”