Why had this pioneer of an alewife, and the others that had come before it, arrived so soon? It is possible that they had migrated up Stony Brook before. All mature alewives--a majority seem to be four years old--are moved by sexual development and swim inshore when the temperature of the fresh or brackish water has turned warmer than the salt water from whence they came. The earliest comers often appear to be larger in size. This suggests, at least, that they may be older and that they have spawned in that run before. The latest to come seem to be the smallest, and therefore the youngest. Alewives, like other fish, seem to have a tendency to keep growing, though there may be a maximum size reached in their fifth or sixth year. The only conclusive way to tell their age is by microscopic examination of their scales, which reflect each spawning year and its physical changes. Work done by Keith Havey on alewives in Maine shows a minimum of alewives spawning at three years of age and the largest number in the four- or five-year-old range. No scales were found which reflected more than two spawnings. As to size, he gives a sampling of their length in inches which graduates up from 11.25 inches in the three-year-old fish to 11.80 in the four-year-olds, 12.35 in five-year-olds, and 12.80 in the six. The female alewife, incidentally, is a little larger than the male. Possibly then, these early alewives at Stony Brook were the oldest, and because of that they might have been the most practiced at finding their way. I am told that, with new fish ladders, observers have noticed the earliest arrivals seeking and passing through them more readily on the second year after construction than on the first, which leads to the belief that they have been through before. Age may improve the alewife in prowess, though it is a fish of crowds, and not one to strike out much on its own. The “homing instinct,” still unfathomed, but about which I will try to say more later on, brings them back to their streams of origin with almost united force. [Illustration] So my lone alewife marked the greatness it preceded, though it was early, in early and still undecided weather. At first the sleet, hail, flurries of wet snow came in profusion, stabbing between the sunshine, as though nature, before making its next terms known, was full of passionate unease. Then wings of warm rain would beat in over the Cape, to slash and curve and follow along trees and houses, through inland ponds, across the ridges and hollows, and the wind poured behind in great gusts, trying, it seemed, to shake a tight world loose. Underneath the struggling air many things waited for more chances in the sun, but under the stars, on foggy evenings or bright days, the singing of peepers in pools, ponds, or boggy land would swell and widen everywhere.