This blog post is based on personal photography outings and detailed field observations, documenting the rich and subtle transition from summer to fall through the migratory journeys of shorebirds and seabirds on Hilton Head Island.

As summer wanes on Hilton Head, the shift to fall is marked not by the approach of peak hurricane season, but by the vibrant arrivals and restless movements of migrating birds along the coast that forms part of the Atlantic Flyway. From the vantage point of the receding tides at Port Royal Sound to the sandbar’s edge, careful observation unveils the pulse of migration—and the living signs of a season in transition.

Black Skimmers and Early Arrivals

After a morning of soaking rains, I went to the beach as the tide receded. Great Egrets and Snowy Egrets gathered in the tidal pools, standing together in the pluff mud. The scene was mostly calm, with the birds resting, preening, and quietly fishing. When one of the egrets did manage to spear a fish, there was a brief burst of pandemonium before things quickly settled down again. The filtered, moody light created a high key effect in the camera, giving the whole scene a distinctive look.

A large flock of Black Skimmers, including many juveniles, worked the “delta” where a small tidal creek meets Port Royal Sound. Lying flat in the sand, I watched a few skimmers break from the large resting flock and start their feeding cycle: circle around and return repeatedly to the rivulets in the sand. From close range, I could hear the slurping sound as they skimmed the water with their unique low mandibles. When I moved slightly to adjust my camera, the skimmers squawked in response, but quickly settled back to their feeding routines. Their presence, especially with so many young birds, is an early sign that migration has begun, and some will likely stay to overwinter.

At the wave line, two Ospreys floated and bathed vigorously, with one emerging holding a flat-looking fish in its talons, possibly a flounder. Along the wrack line, a Willet fed back and forth. New shorebirds—many still showing breeding colors, including a Black-bellied Plover, Sanderlings, and a flock of Semipalmated Plovers—fed actively, the plovers pip-squeaking loudly as they foraged. Walking back along the edge of the dunes and marsh, I observed several pairs of Eastern Kingbirds, summer residents, flitting about and settling on the tall stalks of sea oats. This morning highlighted the overlap of lingering summer residents like Eastern Kingbirds and the arrival of migrating shorebirds along the coast.

Dawn’s Threshold—Night Herons and Roseate Spoonbill

In the dark before first light, I made my way across the mudflats exposed by the outgoing tide. The first birds I noticed were night herons—one Black-crowned and two Yellow-crowned—fishing in a tidal pool close to shore. The Black-crowned Night Heron gave out a loud, barking squawk and moved off a few feet. As it grew lighter, a juvenile Roseate Spoonbill, smaller and pale pink compared to adults, appeared and fed quietly with several Snowy Egrets.

When I reached the sandbar, I found my spot to sit and observe. At dawn, I could distinguish by sight and sound Royal Terns, Forster’s Terns, and a flock of Black Terns. The Black Terns were in various stages of plumage: some had solid black heads typical of breeding season, while others were noticeably mottled as they transitioned into their paler, non-breeding plumage.

Black Tern Migration on Hilton Head

The Black Tern’s migration is unique among North American terns. Unlike most terns that breed and migrate along ocean coastlines, Black Terns breed almost exclusively in freshwater wetlands across the continent’s interior—especially the Prairie Pothole region of the northern Great Plains and southern Canada. What makes their journey distinct is the pronounced eastward shift: after the breeding season, both adults and young leave these inland marshes and move east to join the Atlantic Flyway, crossing from the central U.S. and Canada to the Atlantic Coast before continuing south to wintering areas in the Caribbean, Central, and South America.

Most other tern species either stay along a single coastal flyway or migrate along more direct north-south lines. In contrast, the Black Tern’s considerable “crossover” from interior marshes to the oceanic flyway is a striking feature of its migration—tracked by modern nanotagging and confirmed by ornithological studies. This long migratory detour makes locations like Hilton Head Island especially significant, as they are key staging points during a narrow window in late summer and early fall.

This complex route highlights how the Black Tern connects North America's heartland wetlands to coastal environments hundreds of miles away, further underscoring their presence as a signature indicator of the Atlantic Flyway in motion.

Why Their Sightings Signal Migration

Peak Timing: August and September are peak months for Black Tern migration along the South Carolina coast. Observations are common from early August through late September, reflecting their movement en masse past Hilton Head on their way to tropical wintering grounds.
Plumage Transition: During migration, Black Terns are seen in a variety of plumages. Some retain nearly all-black breeding feathers, while most are transitioning to their light gray and white winter look, with a distinctive dark ear spot on each side of the head. Such mixed plumages, often seen in a single flock, highlight the ongoing seasonal change reflected in these visitors.
Pulse of the Atlantic Flyway: Because Black Terns are only present on Hilton Head for a brief migratory period and their numbers spike specifically in late summer and early fall, their sighting on local sandbars and beaches is an unmistakable sign that migration is underway.

Breeding Plumage on the Move: More Signs of Migration

More evidence that shorebird migration is underway comes from the presence of shorebirds still wearing their striking breeding colors. Flocks and individuals of Black-bellied Plovers, Piping Plovers, Dunlin, Sanderlings, Least Sandpipers, and Semipalmated Plovers can be observed in August and September with many still displaying remnants of their bold, bright summer plumages as they refuel along the mudflats and beaches.

Black-bellied Plovers are widespread during migration and are often seen in full breeding attire, with their signature black breasts making them easy to distinguish.
Piping Plovers and Dunlin also feature on the sandbars and mudflats, their subtle-to-rich hues reflecting their recent arctic nesting—these species are considered high conservation priorities and use the South Carolina coast as a crucial stopover or for overwintering.
Sanderlings, Least Sandpipers, and Semipalmated Plovers are abundant during this migration window, often noted in mixed-age and mixed-plumage flocks. Bright juvenile and adult feathering provides wonderful study opportunities and more proof that migration is in full swing by late August.
Collectively, the spectacle of shorebirds mixing breeding and non-breeding plumages is a sure sign that the seasonal transition is unfolding across Lowcountry barrier islands and beaches.

The Subtle Art of Seasonal Change

During these outings, I watched mixed flocks of shorebirds of different ages feeding together, sometimes breaking into brief squabbles, then settling back into resting or foraging. The marshes, mudflats, and sandbars provided constant activity: birds feeding quickly as the tide went out, preening, and occasionally taking flight before returning to feed again. The sounds were a mix of sharp calls and quieter background noises, blending with the shifting wind. Observing these regular patterns along Hilton Head’s coast, it’s clear that migration is underway and the landscape is changing from summer toward fall.

Pointe of the Season: Witnessing Fall Migration on Hilton Head Island