The finches of Galapagos are an iconic symbol of evolution in action: each species neatly adapted to its island's environment, thanks to enormous time spans and total isolation. But isolation is not so easy to maintain these days. Despite heroic efforts by the government of Ecuador to control the movement of critters from island to island, sometimes even just putting your foot on the ground can radically affect a landscape, or even alter the fate of Darwin’s famous finches.