First a story about science. In the early decades of the twentieth century, the British ornithologist Henry Eliot Howard made a remarkable discovery. In a series of books culminating in his Territory in Bird Life of 1920, Howard described the instinct for the possession of "territory" that he had found in warblers and other birds. The drive to claim and defend a clearly bordered portion of the landscape, he argued, was the controlling factor in the birds' social life. Among other things, it regulated which males could breed, kept the population in balance with its resources, determined how the birds were spaced across the landscape, and explained why they sang.1