When do birds start migrating

Spring Migration: It's All About Timing From January to June, each migratory species has its own special time to return to summer breeding grounds Kenn Kaufman Apr 07, Somewhere in North America, there is probably some kind of migratory movement of birds every day. But spring migration—the mass movement of birds toward their breeding grounds—happens with predictable timing each year. The precise local timing varies, of course, with latitude and elevation. Among the first groups of birds to move north are waterfowl: ducks, geese, and swans may begin migrating as soon as frozen lakes and marshes start to thaw.

Even in the northern states, flocks of waterfowl may arrive in late February. Also on the move this early are some species that migrate mostly within North America, spending the winter as far north as they can. They include killdeer and red-winged blackbirds.

Some birds of prey also start to migrate in early spring. Bald eagles, rough-legged hawks and red-shouldered hawks are actively moving north even while wintry conditions still prevail. Other surprisingly early migrants include purple martins, returning from South America and reaching Florida and Texas by late January and making it to northern states by the end of March.

Many native sparrows tend to be early migrants, with large numbers moving in southern states in March and in northern states by early April. The fledglings are still very weak and need to gain a lot of weight to survive. They are also not great flyers yet and are just beginning to get used to the new world they have launched into.

This makes fledglings an easy target for predators, especially outdoor cats, which often spend time hunting for birds in suburban gardens. After a few more weeks when they are strong enough, the fledglings that survive will leave their parents to explore their surroundings.

The environment changes a lot over the course of the summer. Catbirds must shift their diet with the changing season to get ready for migration. By the end of the summer, there are fewer caterpillars and other insects to eat. Luckily, the plants that flowered in spring and early summer will begin to produce berries. Adding fruit to their diet helps catbirds gain a lot of weight in the form of fat.

Based on tracking data, including light-level geolocator tags, we know that catbirds from different breeding grounds make their fall migration to different locations.

The routes the birds take during migration also differ, even among birds that leave from the same breeding location. For example, some of the catbirds we have tracked from Washington, D. The amount of time birds spend migrating also varies by individual. The science of migration is pretty exact, and birders have learned to use weather and historic records to tell when a particular species will be migrating through—give or take a few days.

The BirdCast put out by the Cornell Lab of Ornithology lets you know exactly what to look for in your locale. May is the best. May is the bestest. Though some birds start breeding earlier larger birds like owls and eagles begin building nests and laying eggs in the winter , returning spring migrants are looking to start nesting and raising young right away.

Birds that shack up in your area will show up and start claiming territories, singing their little hearts out to stake their claim and try to woo females.

Migration trails off by the beginning of June, as most species are well into their breeding cycles. The thrills of April and May are over, and nesting birds have settled into the quick and quiet routine of raising young. Otherwise, just enjoy the sunshine.

Mid-summer is when the birding gets quiet—literally. Birds are still raising young and not being very vocal because they no longer need to attract a mate or defend territory. Birders take it easy in the summertime. That is, u nless they're into shorebirds: This is prime time for those long-legged lookers. Some species will have left their A rctic breeding grounds by late June, which means there may be steady streams of adults and then juvenile birds in July and August.

Head to the marsh or check some fields after a heavy rain. Or, relax, have some ice cream, and learn to identify butterflies, which are most numerous and visible on sunny afternoons.

Fall migration perks birders back up. Every northern summer, millions of seabirds that breed in the Southern Hemisphere are on the move. Chasing an endless summer as trans-equatorial migrants, these masters of migration cross into northern oceans in search of food and warmer weather. Perhaps no other species are as famous for this as the Pacific Ocean populations of Sooty and Short-tailed Shearwaters.

These salty seabirds breed around Australia and New Zealand generally arriving at their breeding colonies in October, laying eggs in November, and fledging chicks by late April. Departing the oceans of these areas in the southern fall, they arrive in Japan, Alaska, and California by May and June.

By mid-summer in the Northern Hemisphere, millions of Sooty Shearwaters are found just offshore in one of the greatest migration spectacles in North America. Wherever you live, be sure to look for these, and many other amazing summer migrations.

Much of our current knowledge on bird migration is the result of careful observation by birders, such as you, during all months of the year, including summer. With advanced technology allowing for an increased precision in migration knowledge in both time and space, Audubon and partners can help protect migratory birds and the places they need throughout their annual cycle, now and into the future.

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