Using DNA Metabarcoding and Citizen Science to Assess the Diet of Owned Domestic Cats

Various methods have been attempted to quantify hunting and consumption of wild prey by domestic cats, but molecular analysis of their scat using DNA metabarcoding has rarely been attempted. In this study, we relied on owner-collected scats (n = 32) from litterboxes and backyards to test whether this methodology could be used to detect consumption of wild prey by owned, indoor-outdoor domestic cats, and whether pooling scat samples could enhance efficiency or would result in a loss of resolution. We monitored eight cats for an average of 12.1 days, collecting an average of four scats from each. Metabarcoding revealed only one instance of wild prey consumption, a California vole (Microtus californicus), despite the owner not witnessing any prey returns during the 24-h period prior to scat sampling. Conversely, in three instances where the owner reported returns of intact prey by their cats, prey DNA was not recovered, presumably because no prey parts were consumed. Thus, consumption and owner-reported capture of prey may be poorly correlated. Pooling scats did not influence detection of ubiquitous, abundant taxa such as chicken contained in their owner-provided food, but consumption of a vole by one cat was only detectable in the scat tested alone. Pooling scats for analysis may sacrifice sensitivity to detection of wild prey. Our study suggests that DNA metabarcoding may be a viable method to detect consumption of wild prey by owned domestic cats; however, a larger sample size is needed to investigate the biodiversity of taxa in the diet, as the frequency of prey consumption by cats may be lower than that of prey capture.