A Comparison of Stomach and Fecal Samples for Diet Analysis of Grey Kangaroos

In an experiment with four captive eastern grey kangaroos, Macropus giganteus, microscopic analysis of both stomach contents and faeces did not reflect the ingested dry weight proportion of most plant species in a fed diet. However, close agreement was obtained by correcting for unidentifiable microscopic fragments of plants. This suggests that differential digestion may not be as important an artefact of microscopic diet analysis as previously reported. Provided corrections are made, faecal analysis may be as reliable as stomach content analysis for describing relative proportions of plant species in the diet of macropodids. In contrast, differences in proportions of plant species between stomach and faecal samples from free-ranging western grey kangaroos, Macropus fuliginosus, suggest that faecal analysis may not be suitable for quantitative studies of diet selection (comparisons of plant species proportions in the diet with species proportions in the field) in areas with heterogeneous vegetation. In these situations, samples of stomach contents are considered more appropriate.