The origin of stomach oil in marine birds: Analyses of the stomach oil from six species of subantarctic procellariiform birds

The stomach oil produced by many marine birds of the order Procellariiformes is an important aspect of their breeding ecology. Fifty-seven samples of stomach oil from six species of subantarctic sea birds were examined by thin-layer and gas chromatography to determine the degree of variation in stomach oil composition between individuals of the same species. The wide variability detected, the typically marine composition of the component fatty acids and alcohols of the wax esters and triacyglycerols examined and the presence of pristane, squalene, and astaxanthin in the stomach oils all indicate that the bulk of the oil is derived directly from the food. This is in contrast to the nutritive fluids produced by secretion in several other groups of birds. Many of the stomach oils contain large amounts of wax ester and marine birds represent a significant link in the marine food web for the reconversion of zooplankton wax ester to triacylglycerol. No substantial offshore pollution by petroleum hydrocarbons was indicated by the samples; stomach oil samples from pelagic birds may be valuable in monitoring offshore pollution.

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