Gateholm is a tidal island or 'half tide islet', accessible only at low tide. We were there at just the right time for a visit, with the tide going out, and so we scrambled down to the exposed rocks and then up via a large inclined slab of rock on the eastern side. Across the level summit of the island is a thick cover of grass and a trail of sorts, visible from the mainland, which leads to a cairn at the far end. But my main experience of this small island was its emptiness, its sheer lack of observable features, and the exposure it affords to the weather. On this day the sun was out, but there was also a strong northerly wind. Underfoot the grass was thick (no rabbits!) and the weave of vegetation had a number of hidden hollows and holes, making walking an unsteady experience.
The Ordinance Survey map for the area indicates a 'settlement' on the island in the gothic script used to denote the presence of historic features. But, walking across the island we just couldn't see it. The island is deserted, empty, unless you look much more closely for physical traces or, conversely, from much further away. In aerial photographs the evidence of buildings is clear, and the suggestion is that there was a settlement here in the late-Roman/early medieval period with the isolation of the island and its steep sides providing the inhabitants with a naturally defensive position.
I like to think of myself as observant, taking Henry James' exhortation - 'Try to be one of the people on whom nothing is lost' - as a personal motto. But sometimes I just can't see what's there, it simply isn't sensible, because I haven't developed the competence to see it.