A new automated monitoring device for small carnivores, the Scentinel^®, is a ‘smart’ tracking tunnel. It records time, date, weight and a digital photograph of every animal visiting it, and stores the data to be downloaded on command. This paper describes a field trial aiming, first, to verify the Scentinel’s species identifications against those given by footprint tracking papers, and then to compare the efficacy of routine monitoring with the Scentinel against standard tunnel tracking methods. In February–April 2005 we identified to species 98% of 1559 visiting animals, mainly hedgehogs (Erinaceus europaeus), ferrets (Mustela furo), cats (Felis catus) and rats (Rattus rattus and R. norvegicus) in 1718 Scentinel-nights. In May–June 2005 we set up three monitoring lines 1 km apart, each with 10 tracking tunnels and two Scentinels. We recorded 656 visits by ship rats (Rattus rattus), 88% of them on only one of the three lines, in 198 Scentinel-nights (over 5 weeks). The 30 footprint tracking tunnels set intermittently (360 trap-nights) recorded high (70–100%) tracking rates on all lines. The presence of a stoat (Mustela erminea) was detected by both methods, but earlier by Scentinels than by tracking tunnels. These results confirm that it is possible to use automated devices to record detailed monitoring data on small carnivores in remote areas over long periods, unaffected by interference or bait loss from common non-target species.