Progressive ontogenetic niche shift over the prolonged immaturity period of wandering albatrosses

• Published in: Royal Society Open Science
• Main Authors: Alice Carravieri, Henri Weimerskirch, Paco Bustamante, Yves Cherel
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2017
• Subjects: stable isotopes; mercury; moult; feeding ecology; subtropics; subantarctic; Science; Q; Diomedea exulans
• Online Access: https://doi.org/10.1098/rsos.171039; https://doaj.org/article/0a264245ae1b463c8b6848dba32f6859

Very little is known about trophic ontogenetic changes over the prolonged immaturity period of long-lived, wide-ranging seabirds. By using blood and feather trophic tracers (δ13C and δ15N, and mercury, Hg), we studied age-related changes in feeding ecology during the immature phase of wandering albatrosses Diomedea exulans when they gradually change from a pure oceanic life to visits to their future breeding grounds. Immatures fed in subtropical waters at high trophic positions during moult. Between- and within-individual variations in isotopic niche were very high, irrespective of age, highlighting wide-ranging exploratory behaviours. In summer, while acting as central-place foragers from their future breeding colony, individuals progressively relied on lower trophic level prey and/or southern latitudes as they aged, until occupying a similar isotopic niche to that of adults. Immatures had exceptionally high Hg burdens, with males having lower Hg concentrations than females, suggesting that they foraged more in subantarctic waters. Our findings suggest a progressive ontogenetic niche shift during central-place foraging of this long-lived species.