The Seaside Sparrow (Ammospiza maritima) is a stocky, dark grayish-brown sparrow found exclusively in coastal salt marshes along the Atlantic and Gulf coasts of North America. It is identified by a distinct yellow spot before the eye, a white throat with dark side bands, and a large, pointed bill. As a habitat specialist, it remains in its range year-round, foraging on the ground and in low marsh grasses for seeds and invertebrates.
Learn to identify
Adult Seaside Sparrow photographed in June at DuPont Nature Center, Delaware.
Learning lesson · openly licensed photographs, labelled by BirdBot; labels checked against the cited sources and approved by AI
Yellow spot by the eye: a small yellow mark in front of the eye. Long bill: long-billed for a sparrow. Pale whisker stripe: below grey cheeks; throat is white. Short, spiky tail: short and pointed. Grey and drab in a salt marsh? Look for the yellow spot.
Colour varies by region; Cape Sable birds are greener above.
Sources: Audubon Guide to North American Birds: Seaside Sparrow · Wikipedia: Seaside sparrow (revision 1321646159)
Photo: DMSDMS215, CC BY-SA 4.0, via Wikimedia Commons; labels added by BirdBot.
Seaside Sparrows are compact birds, typically measuring 12.95 to 14.99 cm in length with a wingspan of 18.03 to 20 cm. Adults weigh between 19 and 28 grams. Their plumage is dark grayish-brown on the upperparts and lighter on the underparts, with some darker streaking. The shade can vary among subspecies, but the key field marks remain consistent.
These features distinguish the Seaside Sparrow from similar marsh birds like the Sharp-tailed Sparrow, which lacks the prominent yellow eye-spot.
Seaside Sparrows are habitat specialists that rely on coastal wetlands dominated by clumped halophyte plants and dense grasses. They use salt marshes for both breeding and feeding, spending much of their time on or near the ground within the marsh vegetation.
According to AviList v2026, the species range includes tidal marshes along the Atlantic coast from southern Maine southward to northern Florida, locally in southern Florida, and westward along the Gulf coast to southern Texas and far northeastern Mexico. The bird remains in its range year-round.
Outside of the breeding season, Seaside Sparrows are solitary. They move through their habitat by flying through the marsh grasses or hopping on the ground to forage. During the breeding season, they form pair-bonds, with males establishing territories through song and physical displays.
Their territories are nest-centered, typically ranging from 100 to 10,000 square meters, with an overall home range of 200 to 20,000 square meters. Males defend these areas from rival males using warning calls and, occasionally, mid-air fights involving pecking and clawing.
Seaside Sparrows are omnivores. Their diet includes seeds, leaves, and fruits of halophytic plants, as well as small invertebrates such as insects, amphipods, and mollusks. They employ several foraging techniques:
The breeding season occurs during the dry season, beginning in March and lasting through July. The breeding interval averages 67 days across tidal marsh populations. The female constructs a tight cup-shaped nest out of fine grasses, placed 14 to 28 cm above the substrate to avoid tidal flooding. The nest is often partially covered by adjacent marsh plants.
A typical clutch contains approximately 3 eggs. Incubation lasts about 12 days, starting as soon as the penultimate egg is laid. The female handles all incubation, while the male forages. Once the chicks hatch, the male helps feed the offspring, allowing the female to leave the nest for short periods. Fledging occurs 7 to 10 days after hatching, and independence is reached at 33 days.
Seaside Sparrows use up to 27 different visual or vocal displays to communicate with mates and rival males. These include raising forehead and crown feathers and making warning calls. Their primary perception channels are visual and auditory, and like many bird species, they can see ultraviolet light.
The Seaside Sparrow is currently listed as Least Concern (LC) in the IUCN Red List, as recorded in AviList v2026. The species is sensitive to habitat changes, as it is a specialist of tidal salt marshes. Protecting and restoring these habitats is crucial for the species' long-term stability.
Observing Seaside Sparrows requires patience and respect for their sensitive habitat. Here are some practical tips for ethical birding:
By following these guidelines, you can enjoy observing this unique species while helping to protect its habitat.
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