La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Using eggshell membranes as a non-invasive tool to investigate the source of nutrients in avian eggs
Auteurs :	Steffen Oppel, Auteur ; Abby N. Powell, Auteur ; Diane M. O'Brien, Auteur
Type de document :	Article
Dans :	Journal of Ornithology (150(1) JAN 2009)
Article en page(s) :	109-115
Langues:	Anglais
Résumé :	Development of minimally invasive techniques to collect nutritional information from free-living birds is desirable for both ethical and conservation reasons. Here, we explore the utility of waterfowl eggshell membranes to determine the nutrient source of egg formation by using stable isotope ratios. We compared delta(13)C and delta(15)N of membranes from complete king eider (Somateria spectabilis) eggs to membranes of hatched or depredated eggs of the same clutch remaining after incubation. Despite large variation among membranes (delta(13)C: -26 to -14%) we found a highly predictable relationship between delta(13)Cof complete egg membranes and remaining ( hatched or depredated) membranes from the same clutch. We did not find a consistent change in either delta(13)C or delta(15)N of eggshell membranes during incubation. We suggest that isotope ratios of membranes can be used to determine the source of exogenous nutrients for egg production in income breeders, and that membranes may offer a clutch-specific reference point for dietary nutrients ('income endpoint') in isotopic mixing models quantifying nutrient allocation in capital or mixed-strategy breeders.

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