Efficacy and effects of diet sampling of albatross chicks
Although a variety of techniques (including water-offloading, and spontaneous and induced regurgitation) are used routinely to obtain fresh stomach samples from seabirds, there have been few studies of their efficacy or potential deleterious effects. In this study, sampling of Black-browed (Thalassarche melanophrys) and Grey-headed (T. chrysostoma) Albatross chicks by induced regurgitation had no effect on subsequent survival or fledging mass. In addition, the samples obtained were large (on average, 676 g and 756 g, respectively, which was 19% and 23% heavier than the average meal mass in a previous study). Notwithstanding the analytical biases associated with differential prey-digestion rates (which also apply to samples from adults), the advantages of this technique are that it is non-invasive, rapid (<1 min), requires minimal training and, compared with handling of adults, does not entail a desertion risk. Induced regurgitation of chicks is therefore highly recommended for routine monitoring of diet in Procellariiformes.