White-rumped Swifts

I had walked past that tiny cave dozens of times, but that morning with some visitors, I ventured into its mouth. Perhaps there would be some bats and certainly the view across the dehesa woodland pasture was superb. The ground was still parched dusty-yellow, contrasting with the dark green forms of the holm oaks. We stood just inside the entrance and took in the scenery. Suddenly whoooosh! I was aware just of quite a large animal flying past our heads (we could feel the air move) and seemingly disappearing ahead of us. A split-second impression. Was it a bat? Well, it seemed a bit too big and I was sure that I had seen a flash of white. A minute or so later, it swept out again, also just a few centimetres from our heads and this time, although the view was almost as brief, it was obvious that it was a White-rumped Swift. This is quite a mystery species. Its home is Africa, where it is widespread and common. It was first recorded in Spain in Cadiz province in the late 1960s and was...