"Almanac"—the word comes from the Arabic al-manakh, meaning "the calendar," earlier "the weather," deriving ultimately from ma-, "a place," and nakha, "to kneel," or a place where camels kneel, a seasonal stopping place, a camp or settlement. Coming as it does from a nomadic human society, it is a fitting word as we talk about our bird life, and their travels and destinations, all as they are influenced by the season of the year.
In order to understand the vital interplay of time and space as they determine which birds they'll bring us, let us first set aside time to deal with space. For birds, Ohio's longitude has less to do with time, except as it determines the diurnal rhythms of night and day, and as it figured eons ago in the shifting of continents, where our present longitude marks our place between mountain ranges, at the edge of the feathering-out of the great prairies and the great forests, and consequently midway between the great north- and southbound rivers of birds in the Mississippi and Atlantic flyways. Our latitude, by contrast, is all about time for birds—their seasonal movements north and south, their life cycles along the way, the timing of migrations and even vagrancy, the changing length of daylight and the intensity of Earth's magnetic fields, even their habitats as developed in the topography of our land as formed by mile-high glaciers moving latitudinally thousands of years ago, forming our plains and hills, Lake Erie, and the Ohio River.
Survival for birds means successful breeding, and for this success timing is everything. For migrants, early arrival at the breeding grounds is balanced against the risk of arriving too soon to find adequate food; attempting a second brood must be balanced by the risk of an early reduction in food sources. The phenology of predators, frosts, food sources, leafing of local plants, rain cycles, etc., all affect breeding success, and the species we see have successfully adapted to these influences to remain with us today.
Humans have recently (here, over the past two hundred years) radically influenced some of these influences, upsetting delicate balances, and our bird life is changing as a result.
We have removed some predators, and encouraged the proliferation of others. We have apparently caused climatic warming, with earlier springs and later winters. We have introduced exotic animals and plants. We have bulldozed and burned and filled in and poisoned bird habitats. We allow birds to be killed in great numbers, but not, we reassure ourselves, in numbers too great to diminish them. Our effect on the life cycles of birds is dramatic, ongoing, and uncertain as to ultimate outcome.
Reassuringly, it is still possible to discern primeval patterns of birds' natural life cycles throughout the year. Birders find the continuation of these cycles deeply satisfying as a continuous manifestation of the renewal of life, and a way to measure and better understand, during our short span, the passage of time.
Fifty or more species of our birds remain pretty much equally abundant year-round, present in good numbers in every month. Many are the most familiar of our familiar birds, but even to them the calendar brings profound changes. The crows, robins, blue jays, and song sparrows we see year-round are not always the same birds, as these are at least in part migratory species, with different cohorts inhabiting different places at different times of year. Their behavior, too, may change radically over the calendar year: robins that are solitary worm-eaters in summer will flock in winter to eat fruit. The breeding cycle, with all its changes over times, governs all—migrating, singing, incubating, fledging, flocking, molting. Many species have expanded their ranges over recent time—mockingbirds, titmice, cardinals, house finches—and many once-common birds have receded beyond Ohio's borders: prairie-chickens, Bachman's sparrows, and Bewick's wrens are no longer to be found here. Time has claimed some of our birds forever—the passenger pigeon, the Eskimo curlew, the Carolina parakeet—but there is time to save the rest.