The aim of this study was to identify whether bat guano morphology **data** could be used to predict bat diet. We first compared bat diet and bat guano morphology across all the species of British bat. As expected, the guano morphology overlapped too extensively to be able to distinguish between each bat species. It is nevertheless interesting that nine species when investigated individually do seem to correlate between diet and guano morphology. Fig 1B shows it is possible to distinguish a few species from each other for example, P. pipistrellus rarely overlaps with E. serotinus. Generally, however, it would be impossible to distinguish between for example M. daubentonii, P. austriacus, P. nathusii, and P. auritus as they all overlap considerably in terms of guano morphology.