Nocturnal island happenings

Today was the LitNet Training Day/Conference in Clifton House, Belfast.

There were one or two robust exchanges, about which I think I'll post more tomorrow; but meantime, here is something which has been puzzling us for weeks:

Most mornings, we find this floor rug, which lives under Lynn's studio, out on the grass, or strewn across the timber walkway. Clearly it has been dragged there during the night, and to begin with the prime suspect was one of the island foxes. However, when the fox has been in the area we can normally smell him, and there is no smell in the air at all. We have a few theories, from a vixen (which I assume wouldn't mark the area in the same way as a dog fox), to an otter, of which we have recently seen one or two for the first time in years.

It's definitely not Eddie, because during his last walk of the evening we check that the rug is under the studio - but when we let him out first thing in the morning, there it is, some twenty or thirty yards away.

So, we know neither why, nor by what. Most bizarre - all suggestions welcome!