Compiled by David Macdonald and Dawn Burnham from Oxford University's WildCRU, this latest edition focuses on the problems caused by invasive animals on our native mammal species. As highlighted in this report, two of our fastest declining mammal species are suffering from such a threat: water vole numbers have been decimated by predation from the voracious American mink, whilst the red squirrel has suffered numerous impacts at the hand of its America cousin, the grey squirrel. These impacts are compounded by the other issues laid out in this report, and resolving some of these may be the key to preventing the extinction of these two iconic species.