Two weeks ago I was on the northern edge of the Sahara in Morocco watching migrating swallows completing their epic crossing of the desert. They were obviously tired and quietly flew ever northwards, silent but determinedly obeying the timeless instinct of their species. We stood in the late evening sunshine on the golden sand dunes and watched their passing. Something of the wildness and very different lives of the swallows touched us, ever so briefly. It was almost as if a door leading to another alien existence but still on the same planet had tantalisingly been left ever so slightly open for us to sense a different world, but then was quietly closed once they had gone.