Spring on the Wing: Migration Season on the Susquehanna River

Flowing through the heart of Pennsylvania and beyond, the Susquehanna River serves as a vital corridor within the Atlantic Flyway—one of four major migratory bird routes in North America. Stretching more than 3,000 miles from Arctic tundra to the Caribbean and South America, the Atlantic Flyway supports more than 500 bird species. Millions of waterfowl, shorebirds, raptors, and songbirds rely on this pathway each year, and the Susquehanna River and Chesapeake Bay watershed form one of its most important stopover networks.

Migration is triggered by changing day length, temperature shifts, food availability, and genetic instinct. Spring migration (March through May) is often swift and urgent as birds move toward breeding grounds, while Fall migration (August through October, and sometimes into December) unfolds more gradually as birds head south.

Here along the Susquehanna Greenway—the land and water corridor that lines the Susquehanna River—these seasonal movements offer some of the most remarkable wildlife viewing opportunities in the region.

Waterfowl: Early Signs of the Season

As winter begins to loosen its grip, flocks of waterfowl move north along the river

The elegant Tundra Swan and large groups of Snow Goose are among the most noticeable travelers. Their calls often carry across the valley on late winter and early spring evenings.

Because the Susquehanna’s current keeps sections of water open even in cold weather, it provides reliable feeding habitat. Ducks such as Common Merganser and other diving species gather on open stretches of river to rest and refuel before continuing north.

Peak viewing for swans and Snow Geese typically occurs from late February through March, with broader waterfowl movement continuing into April and May.

Shorebirds: A Stop Along the Way

On the Lower Susquehanna, the Conejohela Flats serve as one of Pennsylvania’s most important migratory stopovers

When water levels are right, exposed mudflats provide critical feeding habitat for shorebirds traveling between South America and Arctic breeding grounds.

Spring brings sandpipers, plovers, and other small shorebirds stopping briefly to refuel. Activity typically increases in April and May, while late August through September marks peak southbound movement.

These resting and feeding areas are essential. Without places like the Conejohela Flats, many birds would not be able to complete their long migrations.

Raptors: Riding the Wind

The Susquehanna River corridor also guides birds of prey

In spring, hawks and other raptors move north following the river valley and nearby Appalachian ridges.

Unlike fall—when large numbers concentrate along ridgelines—spring migration is often more spread out and less predictable. On warm days with rising air currents, observers may spot small groups of migrating hawks circling on thermals before drifting north.

Spring is also nesting season. Bald Eagle pairs are active along the river, tending nests and raising young. Other resident hawks begin courtship displays and territory defense, making this a good time to observe breeding behavior as well as migration.

Songbirds: A Moving Chorus

Keep a close watch for returning songbirds

While waterfowl and raptors are easy to spot in open skies, millions of songbirds move quietly along the river corridor each spring. Many migrate at night, settling into riverbank forests at dawn to rest and feed.

March brings familiar early arrivals like Red-winged Blackbird and American Robin. By late April and early May, migration builds steadily. Trees along the Susquehanna fill with warblers, orioles, thrushes, and other insect-eating birds taking advantage of newly emerging foliage.

Peak movement typically occurs in early to mid-May. On calm mornings, attentive listeners may notice how active the river corridor becomes as birds forage and prepare for the next leg of their journey.

The River as a Lifeline

Landforms such as river valleys and ridgelines help guide migrating birds

Just as important are stopover sites—places to rest and refuel. The Susquehanna River and Chesapeake Bay watershed together form the largest watershed on the East Coast, providing a mosaic of habitats that sustain migratory species year after year.

For those who live and work along the Susquehanna, migration is part of the region’s natural rhythm. It connects our communities to landscapes far beyond Pennsylvania and reminds us that the river plays a role in something much larger.

Close to home, the Conejohela Flats is one of Pennsylvania’s dependable sites for observing large numbers and diversity of shorebirds in one place. Other hotspots include Wildwood Park in Harrisburg and the Susquehanna Riverlands in Berwick, as well as several other protected river islands and conserved lands.

A Season to Begin

If you are new to birding, spring migration offers an accessible starting point

A simple sunrise visit to a river access area can reveal more activity than expected. Listen for unfamiliar songs. Watch for movement in the treetops or flocks passing overhead.

Binoculars and a field guide are helpful, but curiosity is the most important tool. Digital resources such as eBird and Merlin Bird ID can help with identification and tracking sightings. For those curious about larger migration patterns, the Bird Migration Explorer at audubon.org offers interactive maps showing where species travel throughout the year.

Migration is one of nature’s great shared experiences. Whether you are birding for the first time or returning each season with a well-worn field guide in hand, the Susquehanna Greenway invites you to look up, listen closely, and become part of a story that stretches from Arctic tundra to the shores of the Susquehanna River.

Looking for a little guidance in the world of birding?

Join the Susquehanna Greenway Partnership, PA Master Naturalist, and the local Audubon Societies for guided bird walks this spring.

• April 15 at 8 am | Berwick at the Susquehanna Riverlands. Led by the Greater Wyoming Valley Audubon Society. Details can be found here.
• April 22 at 8 am | South Williamsport at the Robert Porter Allen Natural Area. Led by the Lycoming Audubon Society. Details can be found here.

 

Featured Image (top) courtesy of Michael Dreese.