Hi @Jennymec , for decades, the only small mammals in the Canberra suburbs have been the Black (Roof) Rat (Rattus rattus) and the House Mouse (Mus musculus). There have also been a few claims for the Norway (Sewer) Rat (Rattus norvegicus). Of course our nearby waterways have the native Rakali (Hydromys chrysogaster) but I dont know of one coming in among houses. However your first and second images do not look exactly like a Black (Roof) Rat (Rattus rattus). I dont know what they do look like. The short tail and dumpy appearance reminded me of Swamp Rat (Rattus lutreolus/lutreola) which we do not have in the ACT. I think this must be R. rattus but I have left it as uncertain. If you can get better images ....