Cape York (north-east Australian mainland) seems a strange place for a "Tasmanian" tiger to turn up, but there have been quite a few mainland thylacine reports over the years. I remember a photo from back in the 1980s from Western Australia, though the provenance of that was rather dubious - see
http://www.naturalworlds.org/thylacine/ ... ings_3.htm. There's quite an interesting one from Adelaide, with some poor quality video, at
https://www.google.co.nz/url?sa=t&rct=j ... Go&cad=rja - the article talks about more footage to come from the Nannup area of Western Australia, but I can't find any subsequent mention of that. Nannup is apparently a hotspot for thylacine sightings however. There's a good review of thylacine mainland sightings at
http://www.naturalworlds.org/thylacine/ ... ings_1.htm, and Tasmanian sightings at
http://www.naturalworlds.org/thylacine/ ... ivor_1.htm. There's a paper on Western Australia sightings at
https://www.dpaw.wa.gov.au/images/docum ... les/90.pdf. I'm not sure what to make of these - some look like hoaxes (e.g. there's a CGI thylacine from the film The Hunter presented as a sighting on YouTube) or misidentifications, but some seem credible. I'll reserve judgement at this stage, but would love to see its continued survival confirmed by actual physical evidence.