This peculiar structure is in a field outside the gates of the Alaksen National Wildlife Area on Westham Island. It is a barn, more or less, slightly smaller than a garden shed, elevated on a pole. It is also a nest box for Barn Owls, although I don't know the history of its use (how often or successful).
Southern BC, including southern Vancouver Island, is at the northern periphery of the range of the western North American population of the Barn Owl. They aren't common, but I suspect are still found throughout the farmlands of the Fraser River delta despite the gradual disappearance of old wooden barns. A few years ago, when I was working at the nature park, a young man came in with a camcorder and showed me a video he had made of a Barn Owl sitting on a Westminster Highway road sign. He had filmed it at 2 in the morning. What was he doing, driving down Westminster Highway at 2 in the morning? He was a pizza delivery man, a very alert and prepared one. There it is again: always take your camera with you.