It is just possible, then, that some spring when the annual run of alewives is smaller than usual, for no apparent reason, you might find an answer to the mystery in a cold season, four years before. After the first young alewives have moved out, having attained the size and response necessary for it, you can see a gradual increase in size from early summer until autumn. One of the unsolved questions is why the earliest to go will not stay longer in the ponds. Why not relax, if a fish can, and eat well until autumn, as in fact large numbers of them do. Were they nearest the outlet? Perhaps the larger fish that begin to appear later on were hatched earlier and therefore came from farther back in the chain of ponds. Of course there is nothing rigid about their timetable, nothing exact about their migratory behavior. Whatever stimulates it, their new momentum takes the form of a gradual circling out. I have heard that in some areas they will start down and then return when they can swim back up the outlet, if the force of the water is not too strong for them. They may be in a state of indecisive action for a while, or so it sounds, but most of them are moved to go at some time before winter sets in, though there have been many exceptions to the rule. John Burns, of the Massachusetts Division of Marine Fisheries, tells me that he saw a “generous school of fry” one January, coming down under the ice of a frozen pond at Bournedale. Perhaps this phenomenon of migration in the young fish is not susceptible of final analysis. Might that be because it is so simple, however complex in detail and circumstance, simple though intangible in the life rhythm it embodies? However slow or fast their response to it may be, the little fish must be obeying an organic, directional drive that goes back beyond history. As a part of their growing up they may develop the same kind of built-in response to the waters in which they find themselves as their parents schooling offshore in the spring; and they come to have an intercommunication that knows its way. It is not the adult call of sexual maturity that moves them, and yet they must have a biological need to start out together on the same living track. I recognize how much an amateur may leave out of his calculations, and only proffer my individual guess that they follow the outward flow of the ponds when they grow to feel a rhythmic, habitual motion in them that responds to it and that belongs in its balance to the whole race of alewives between land and sea. The fresh-water minnows stay where they are, no matter how hard the pull of the waters may be. I have seen them lazing in the shallows while a school of little alewives darted over them, restlessly moving on. And as I followed the young migrants I saw in them a roaming, roving sweep like sea birds made for distant journeys.