Ammospiza maritima
The Seaside Sparrow is a large, dark sparrow, well-named for its preferred habitats of salt and brackish marshes. Although it shares habitat with other shoreline-loving sparrows such as the Saltmarsh and Nelson’s Sparrows, it is noticeably bigger and darker. Sometimes called the “Goldilocks Bird,” this sparrow needs a combination of environmental factors that are “just right” to breed successfully.
Ornithologists recognize seven subspecies of Seaside Sparrow, distributed along the U.S. Atlantic Coast south through the Gulf Coast of Texas. Some of these subspecies are endangered, and one is extinct.
The dark-plumaged “Dusky” Seaside Sparrow subspecies was once resident along the Atlantic coast of southern Florida, in the marshes of Merritt Island, and along the St. Johns River. Its small numbers and tiny range made it especially vulnerable to habitat loss caused by accelerated development, mismanaged mosquito control efforts, and road building. By 1979, its population had dwindled to only six males, five of whom were brought into captivity. The last Dusky Seaside Sparrow died in 1987.
Habitat loss has already claimed one of the Seaside Sparrow’s seven subspecies, and that threat persists, exacerbated by climate change. This distinctive sparrow is also endangered by pesticides. Certain populations face more profound and urgent threats than others, and their vulnerability differs from region to region. Partners in Flight includes the Seaside Sparrow on its Yellow Watch List for species with restricted ranges.
Habitat loss is the primary driver of human-caused threats facing the Seaside Sparrow. Significant portions of the species’ salt marsh habitat have been lost to filling, draining, and diking. The impoundment of marshes is thought to have contributed to the extinction of the Dusky Seaside Sparrow. Ditching, a drainage technique used to curb mosquito populations, has also led to habitat degradation.
Sea level rise has already reduced Seaside Sparrow populations in the Chesapeake Bay, and as it progresses, it will only accelerate the loss of tidal marsh habitats. Rising sea levels due to climate change increase coastal flooding, swamping Seaside Sparrow nests. The increasing frequency and severity of major storms can also impact this species’ habitat.
Seaside Sparrows are vulnerable to the effects of insecticides used in mosquito control. Runoff of pesticides and other chemicals also put the species at risk.
At ABC, we are inspired by birds and driven by our responsibility to ensure no species meets the same sad fate as the Dusky Seaside Sparrow. We engage a wide network of partners to conserve and restore habitat and pursue policy changes to ensure birds and ecosystems are safe from dangerous pesticides and toxins. With science as our foundation, and with inclusion and partnership at the heart of all we do, we are taking bold action for birds like the Seaside Sparrow.
ABC is part of the Atlantic Coast Joint Venture, a highly collaborative partnership working together to coordinate marsh bird conservation along the East Coast. The ACJV is scaling up habitat restoration and conservation techniques in degraded coastal marsh habitats, focusing on species like the Seaside and Saltmarsh Sparrows and the Black Rail.
ABC takes action on the federal and state levels to call for the cancellation or regulation of the pesticides and toxins most harmful to birds. We advocate for strong policies that protect birds, their ecosystems, and communities, and encourage millions to pass on using harmful pesticides at home.
The Seaside Sparrow is large and dark with a long bill. Adults of the Atlantic race are the darkest and dullest, overall plain gray and brown with indistinct, blurry streaking down the bird’s chest, belly, and flanks. The Gulf Coast subspecies is slightly brighter with buffy coloration and more obvious streaking. The Cape Sable race is even more distinctive, with an olive-green nape, striped back, and white breast marked with distinct dark streaking.
Notable field marks for all Seaside Sparrow subspecies are the yellow mark extending from the base of the upper bill to above the eye (called a supraloral spot), a white throat edged by darker “mustache” lines, and a long, almost spike-like bill.
The male Seaside Sparrow usually sings from a conspicuous perch above the marsh grasses. Its buzzy song consists of a few rough introductory notes followed by a raspy sigh. The song varies slightly between the different subspecies.
Credit: William Whitehead, XC654373. Accessible at www.xeno-canto.org/654373.
Credit: David Sarkozi, XC416451. Accessible at www.xeno-canto.org/416451.
Credit: Mike Nelson, XC130531. Accessible at www.xeno-canto.org/130531.
The name “Seaside Sparrow” suits this denizen of the Atlantic Coast’s tidal marshes. Nearly all subspecies are habitat specialists in tidal salt marshes and brackish (a mix of salt and fresh water) marshes. The Cape Sable subspecies is the exception, inhabiting freshwater marshes in the Everglades.
Specific Area
East and Gulf Coasts of the United States
Range Detail
Seaside Sparrows nest along the Atlantic and Gulf coasts of the United States, from southern New Hampshire to southern Texas.
Did you know?
Of the seven recognized subspecies, some are migratory and some are year-round residents. Those in the northeastern subspecies (maritima) migrate to the southeastern U.S. in the winter months.
The Seaside Sparrow is built for life in the salt marshes, dynamic, transitional zones that merge sea and land and experience near-constant change. The large, strong feet and legs of the Seaside Sparrow allow it to hold fast to grasses and move nimbly on mudflats. They are strikingly communicative, using their wings, tails, and even grasses plucked from the ground and held in their beaks to convey a variety of messages.
The Seaside Sparrow’s large feet help it balance and run over muddy, marshy ground. It uses these big feet to “double-scratch” (leaping forward and then scratching backward) in dead grasses and ground cover, exposing hidden prey. The Seaside Sparrow eats seeds, insects, spiders, and other invertebrates, gleaning prey from vegetation and the ground. It darts quickly through the marsh grasses in pursuit of prey, even wading into shallow water to probe beneath the surface. Its spike-like bill is particularly useful for probing into mud and picking through dead clumps of cordgrass. It also eats mollusks, small crustaceans, and seeds of marsh grasses.
The Seaside Sparrow is monogamous during its nesting season. In nonmigratory populations, pairs may stay together year-round. Even in migratory populations, females sometimes repartner with their mate from the previous nesting season.
The male sings to claim a nesting territory that can vary greatly in size, from a quarter-acre to over two acres. He displays to visiting females by singing, calling, and raising his wings.
The female Seaside Sparrow selects a nest site within her mate’s territory, usually in taller marsh grasses about 6 to 12 inches above ground to avoid flooding. She builds a cup-shaped nest of grasses lined with even finer grasses, often with a canopy or dome made by pulling nearby live plants over the top. This species will re-nest if its nest is flooded or predated.
The female Seaside Sparrow lays a clutch of two to five white eggs that are speckled and splotched with brown. Only females incubate the eggs, but both adults feed the nestlings, which grow quickly and leave the nest nine to 11 days after hatching.
Once fledged, young Seaside Sparrows often gather in small flocks, sometimes joined by adults in the winter.
Related News & Stories for This Bird
Wetlands are wonderful places for birds thanks to their abundant offerings of food, water, and shelter. The long grasses of marshes offer a hideaway to secretive birds like the Saltmarsh Sparrow, which nests just above the tide line on the Atlantic coast of the United States and synchronizes its ...
Join the flock! Your donation helps preserve the habitats that birds need to survive.