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Wildlife Migration

New Jersey's coastal regions provide critical habitat for many migrating species in the Western Hemisphere.

The New Jersey coast is an essential stop in the global migration of many birds, marine animals, and insects. Dolphins, seals, fish,  hawks, eagles, warblers, bats, and butterflies are just a few of the animals that utilize New Jersey's coastal habitats. Although the  migration journey may be fatal for some, the benefits of finding alternative food sources and breeding site with less competition outweigh the cost for the species as a whole.


More than 400 different bird species have been seen during the peak of migration on the Cape May peninsula. Song birds, birds of prey and shorebirds all migrate through here.

For migratory birds that may have traveled thousands of miles, the opportunity to rest and regain their energy at coastal beaches, coastal marshes and barrier islands of the Barnegat Bay Region , Sandy hook region and the Delaware Bay is critical to survival. Island Beach State Park, Cattus Island County Park. and Great Bay Boulevard Wildlife Management Area are teeming with migrants in the spring and fall. Some, such as the warblers, thrushes, tanagers, flycatchers, and orioles take up summer residency in the region's tidal marshes, maritime forests, and pine barrens. They are some of the more popular visitors to Cheesequake State Park, Cape May Migratory Bird Refuge and the Delsea Region. Places such as the Fortescue Glades Wildlife Refuge are inundated with migrants. The fall Neotropical songbird migration is more numerous and concentrated, but in the spring, migrating songbirds display their brightly colored breeding plumage. This is highlighted by thirty different warbler species.

Some birds, such as the clapper rail, sharp-tailed and seaside sparrow, indigo bunting, blue grosbeak, and yellow-breasted chat become summer residents in the coastal marshes. Herons, egrets, and ibis are born in Cape May and Salem county rookeries. Yet these birds often make daily migrations to the tidal marshes of Cumberland county. Ruby-throated hummingbirds also migrate to New Jersey.

Wading birds, such as herons, egrets, and ibis can often be seen foraging in this region. These summer residents gracefully pluck crabs and other prey from the muddy tidal and freshwater wetlands. Rookeries in Cape May nurture the newborn while the adults fly back and forth across the peninsula daily in the summer between their foraging areas and nesting grounds.

Ducks and geese are popular winter visitors that can be found floating in local ponds. Black ducks, mallards, snow geese, and Canada geese are some of the species that you might see here as they avoid the extreme cold of northern habitats.

Golden eagles, bald eagles, and 16 species of hawks funnel their way south through the Barnegat Bay, Cape May and Sandy Hook regions in the late fall of each year. Osprey frequently nest and establish spring hunting territories in the bays behind the barrier islands. Join other avid bird watches on the raptor viewing platform at Cape May Point State Park.

Eagles and thousands of hawks migrate through the Delsea Region in the fall of each year. as many as sixty thousand raptors fly through the bayshore area.


Horseshoe crabs have been coming to the Delaware Bay Shore each spring for thousands of years. They crawl along the ocean bottom and swim towards shore where the females lay up to 80,000 eggs in a series of shallow pits just above the high tide mark. The sand-covered eggs incubate in the warmth of the sun for thirty days until the next spring tide washes the tiny horseshoe crabs out to sea where they mature. 

Horseshoe crab eggs provide food for over a million migrating shorebirds from South America each spring. Starved from the long intense journey to the bayshore, red knots, semipalmated sandpipers, ruddy turnstones, sanderlings, and dunlins may almost double their weight while replenishing their energy supply on the horseshoe crabs eggs before continuing on their journey. The horseshoe crabs support the second largest spring migration of shorebirds in the Northern Hemisphere. Without the attraction of horseshoe crab eggs, the fall migration is much less dramatic. However, many shorebirds still stop in the marshes to feed and rest.

Look for horseshoe crabs and migratory shorebirds at Heislerville Wildlife Management Area and other Delaware Bay beaches.


 Dolphins, whales, and seals migrate just offshore along the Atlantic coast moving north and south as the seasons and water temperatures change. Bottlenose dolphins are common summer visitors off the coast of Island Beach State Park. Although they do not have a typical migration, the harbor porpoise, common to the cooler waters of the far north Atlantic, lives inconspicuously off the shore of the mid-Atlantic region during the winter. Look for these marine mammals in the oceanic water of New Jersey.

Although they do not have a typical migration, harbor seals and gray seals are frequently found feeding near the beaches and inlets around Island Beach and Barnegat Light State Parks between December and March.

Loggerheads and other sea turtles, earned north by the warm waters of the Gulf Stream, migrate up the Atlantic coast as far as Nova Scotia during the summer and return to their nesting grounds along the southeastern coast of the United States in the fall. Because their populations are greatly reduced, the sighting of one is an exciting event.

Several types of fish live in the Atlantic Ocean for the majority of their lives and return to the Delaware Bay and the Delaware River to spawn. Shad "run" the Delaware River in late April through June to lay their eggs near its northern headwaters. Their migration is followed closely by sturgeon that migrate as far as Philadelphia. 

Alewife, small members of the herring family, are more tolerant of cooler temperatures, and therefore spawn in early April when the water is cooler. The return to fresh water spawning sites is an exhausting process for these fish which are primarily found in brakish or salt water. 

Weakfish can be found seasonally in the bays from April to October. Unlike many other fish, they spawn all summer long. Bluefish, a very popular sports fish, can be found off the coast during April and May, and much closer to shore in the early summer when they spawn. Winter flounder spend most of their time is the estuaries, and then swim for deeper waters in the warmer summer months. However, summer flounder spend the summer near the shore.

Menhaden lay their eggs in the ocean from December through February. The eggs drift into estuaries of coastal New Jersey where they eventually grow into juvenile fish. The small fish form schools and then emigrate back into the ocean.

Sand tiger sharks, smooth dogfish, sandbar sharks, and hammerhead sharks also migrate into the bays when the water warms up between May and September.

Marine turtles migrate into the warm Delaware estuary each spring to feed on a plentiful source of crustaceans, mollusks, fish, and aquatic vegetation.

Three species of bass have migrations similar to birds, and they fly to the southern states for the winter. There, hibernation is shorter, and food (mostly insects) is more plentiful. Their migration is concentrated at Cape May as they too take the shortest route across the Delaware Bay.


 Thousands of monarch butterflies fly through here on their yearly migration to Mexico and South America. Look for them in late summer and early fall at numerous destinations including Cattus Island County Park, Island Beach,  Barnegat Light State Park and Egg Island Wildlife Management Area.

Dragonflies also migrate, although their migration patterns are still not fully understood. they may be seen in large swarms in Cape May due to the funneling effects of the peninsula.

Copyright 2001- , Terry Muse 
Revised: August 15, 2001
Contact: Terry Muse
Coastal Heritage Trail