‘Now at last we can say that spring has arrived, and with it come flocks of summer migrants, all those little birds that flew away to the warmer countries in the south when it began to get cold last October. Most of them go as far as North Africa and don’t ask me how they find their way there and back again because that is one of the great mysteries of the world. There are skylarks, greenfinches, goldfinches, whitethroats, willow-warblers, golden plovers, blackcaps, swallows, house-martins, chiffchaffs and many more besides, and soon after they arrive they pair up and start to build their nests.’