IV The Reproductive Urge 45 V The Nature of an Alewife 53 VI Puzzles and Speculations 63 VII Port of Entry 75 VIII The Common Night 83 IX The Hunt 89 X Transition: Salt and Fresh 99 XI Up the Valley 111 XII The Imperfect Ladder 121 XIII Persistence 129 XIV Spawning: the Dance 141 XV The Return 151 XVI The Young Follow After 161 XVII The Power of Fragility 175 XVIII Going Out 183 I Waiting Weather It was in March, in comparative ignorance about their lives and habits, that I started looking for the alewives. This is the time of year when a few forerunners usually come in from the sea, in spite of the cold airs and waters that still grip the narrow land of Cape Cod. I had seen these migrant fish before, during a previous season, but from the road, so to speak. I had never followed them as if they challenged communication. The place I started from was the Herring Run in the town of Brewster, part of a little migratory inland route by which the alewives travel up from Cape Cod Bay to the inland ponds where they spawn. At the Herring Run the waters of Stony Brook pour down from an outlet north of these ponds--three of them, all interconnected: Walkers, Upper Mill, and Lower Mill. The flow then goes over a one-and-a-half-mile stretch, first over the fishway, a series of concrete ladders and resting pools built through rocks and high land, the area of the Herring Run, then through a valley of abandoned cranberry bogs bounded by low hills; and finally it elbows through tidal marshes to Paine’s Creek, its mouth on Cape Cod Bay. This little river was called Sauquatuckett by the Indians and was subsequently known as the Setuckett River, Mill Brook, and Winslow’s Brook. At its falling headwaters the first water mill in this region was built, and one of the later mill buildings is still standing--it has an old water wheel that is still in working order and is used to grind corn as a tourist attraction. By the time the mass of tourists arrive the alewife migration, aside from the “fry,” hatched in the ponds and returning to salt water, has about run its course. They can still take pictures of the old mill in July or August, but they have probably missed a more vital antiquity. [Illustration]