Two huge birds resting in Orielton Lagoon as we drove past. They were a lot larger than the kelp gulls in the vicinity and had uniformly dark plumage, but apart from that I didn't notice much at the time. Looking at the photos they seem to be giant petrels, but I am open to other suggestions as it would be a very weird location for this genera.
@Liam.m The regions' ebird moderator flagged these birds as young kelp gulls. I'm not entirely convinced since the plumage and size seemed wrong, but given that is the expert advice I have updated this observation accordingly.
Honestly Ben, that was my first impression, however I went off of your observation re size and colour. I know the Tassie moderator fairly well, and he knows his seabirds so we’ll go with that. I’ll leave it as Kelp Gull for now, but let me know if you’d prefer that I left it inconclusive due to the distance.