Seaside Sparrow Ammospiza maritima Scientific name definitions

Jon S. Greenlaw, W. Gregory Shriver, and William Post
Version: 2.0 — Published July 1, 2022

Photos from this Account

Adult (Atlantic)
Adult (Atlantic)
Adult (Atlantic)
Adult (Gulf of Mexico)

Gulf of Mexico populations have a yellow stripe in front of the eye and a buffy chest with obvious streaking. Note long bill.

Adult (Gulf of Mexico)
Adult (Cape Sable)
Juvenile (Atlantic)

Juveniles are buffier than adults, with a pale eyebrow. Juveniles also lack the rufous patch in the wing.

Juvenile (Gulf of Mexico)

Juveniles have only a hint of the yellow stripe in front of the eye. Note long bill.

Adult (Atlantic)

Medium-sized, hefty sparrow with a long bill. Atlantic populations have a bright yellow stripe in front of the eye and are grayer below with faint streaking. Note rusty wing patch.


Breeds in tidal marshes.

Seaside Sparrow.

Underparts whitish with diffuse gray streaks and strong buffy wash across breast and on sides and flanks. Crown with indistinct, diffuse central grayish stripe bounded laterally by broad brown stripes and streaked narrowly with black. Lores dusky, yellow supraloral spot blends to olive-green over eye. Ear patch gray to blackish outlined below by narrow white or pale buff malar stripe. Broad moustachial stripe gray framed by pale malar and white throat and chin; short postauricular stripe blackish, variably developed. Wing feathers would need to be examined more carefully to determine if this bird is in Formative or Definitive Basic Plumage. In fresh fall plumage, underparts show more orange buff and upperparts tend to be browner than they are when more worn in spring, due to both wearing of basic/formative feathers and replacement with alternate feathers. The longer bill, gray supercilium, and diffuse breast streaks with central spot helps separate this from a Saltmarsh Sparrow. This individual is likely A. m. maritima, the breeding subspecies of New England.

Seaside Sparrow (right) and Nelson's Sparrow (left).

Bill elongate conical, about as long as head, dusky black, or maxilla dark and mandible pale. Nelson's Sparrow is smaller with a slightly more slender bill, browner above, with a stronger, orange-toned pattern on side of head. The distinct dark streaking to the breast suggests A. m. fisheri, the breeding subspecies of Alabama.

Juvenile frontal view (subspecies maritima).

Forehead and crown olive brown streaked finely with black; face with moderately distinct grayish-buff auriculars and buffy supercilium which is yellower in front of eye (supraloral) than behind it; cheek and postauricular area buff, the former bounded below by indistinct dusky moustachial stripe; chin and throat white, tinged buff; breast, sides, and flanks buff, streaked variably with dusky.

Juvenile lateral view (subspecies maritima).

Nape olive brown, unstreaked; back, scapulars, and rump olive-brown, streaked with blackish; streaking on back moderately heavy (produced by alignment of dark centers of many back and scapular feathers) whereas rump streaking shorter and narrower.

Juvenile frontal view (subspecies maritima).
Juvenile Seaside Sparrow.

Back, scapulars, and rump olive brown streaked with blackish; streaking on back moderately heavy. Remiges and coverts dull brownish black, with no evidence of wing-bars; tertials edged with warmer brown, median and greater secondary coverts weak and edged with buff.

Formative plumage dorsal view (subspecies maritima).

The two new inner tertials contrast with juvenile external tertial and the juvenile secondaries.

Seaside Sparrow completing Preformative Molt.

Body plumage in this individual is Formative, which resembles that of Definitive Basic Plumage. The outer primaries are completing grown as part of the Preformative Molt. Note the retained juvenile inner primaries (p1-p4) and outer secondaries (s1-s5) indicating a first-fall bird.

First Alternate Seaside Sparrow.

By late spring, abrasion at barb tips may result in reduction or loss of buff wash across breast and olive on dorsum. Note the brown and abraded primary coverts and the molt limits between the fresher/darker, formative outer primaries and inner secondaries and the retained juvenile middle remiges (p1-p4 and s1-s5), indicating First as opposed to Definitive Alternate Plumage.

First Alternate Seaside Sparrow.

Most changes in plumage appearance between fall and spring occur through feather wear, but there is also facultative prealternate molt of at least some wing feathers, probably necessitated by feather damage caused by abrasive saltmarsh environments. Here, many back feathers and a few inner greater coverts appear to be replaced alternate feathers. The brown and abraded primary coverts and the molt limits between the formative tertials and remaining juvenile remiges indicates First Alternate Plumage.

Alternate plumage lateral view (subspecies maritima).

Similar to Definitive Basic Plumage; appearance at all ages affected by wear of formative or basic feathers along with replacement of at least some wing feathers during prealternate molts.

Alternate plumage frontal view (subspecies maritima).
Alternate plumage dorsal view (subspecies maritima).
Definitive Alternate Seaside Sparrow.

Late summer birds very faded, feathers “clipped,” and plumage essentially patternless. Note a few darker replaced alternate feathers among the back feathers and upperwing lesser coverts. Although worn, the lack of molt limits in the wing indicate Definitive as opposed to First Alternate Plumage.

Definitive Basic plumage lateral view (subspecies maritima).

Lores dusky, yellow supraloral spot blends to olive-green over eye (often thinly edged above by short line of white) and gray behind eye, the composite forming moderately defined supercilium; auriculars gray to blackish, outlined below by narrow white or pale buff subauricular stripe which often curves behind auriculars and becomes brown to dusky buff; upperwing feathers primarily brown.

Definitive Basic plumage frontal view (subspecies maritima).

Chin and throat white, bordered by broad gray malar stripe; ground color of remaining underparts whitish to grayish white, browner on flanks, with indistinct gray stripes on breast (occasionally diffuse spot center breast), sides, and flanks; central abdomen unmarked; undertail coverts pale buff.

Definitive Basic plumage dorsal view (subspecies maritima).

Upperparts predominantly grayish olive, indistinctly streaked and underparts whitish with diffuse gray streaks and strong buffy wash across breast and on sides and flanks when fresh; crown with indistinct, diffuse central grayish stripe bounded laterally by broad brown stripes and streaked narrowly with black; hindneck “bronzy brown” or olive forming collar, shading to grayish olive on side neck.

Individual with leucistic feathers.
Alternate plumage dorsal view; inner tertial replaced (subspecies maritima).
Head detail.

Note, two-toned bill with with tip, tomia, and ventral surface of mandible appearing the lightest.

Juvenile Seaside Sparrow showing bill color.

Note, pinkish-brown, yellowish gape.

Adult showing head detail (Atlantic group; subspecies maritima/macgillivraii).
Lateral view (subspecies maritima).
Frontal view (subspecies maritima).
Dorsal view (subspecies maritima).
Lateral view (subspecies macgillivraii).
Lateral view (subspecies macgillivraii).
Frontal view (subspecies macgillivraii).
Lateral view (subspecies fisheri).
Frontal view (subspecies fisheri).
Dorsal view (subspecies fisheri).
Lateral view (subspecies sennetti).
Frontal view (subspecies sennetti).
Dorsal view (subspecies sennetti).
Lateral view (subspecies peninsulae).
Dorsal view (subspecies peninsulae).
Frontal view (subspecies peninsulae).
Frontal view (subspecies mirabilis).
Dorsal view (subspecies mirabilis).
Frontal view (subspecies mirabilis).
Bird in its breeding habitat (subspecies maritima); New York, United States.
Seaside Sparrow’ breeding habitat (subspecies fisheri); Louisiana, United States.
Bird in its breeding habitat (subspecies peninsulae); Florida, United States.
Example of black needlerush marsh habitat, Florida, USA.
Bird in its breeding habitat (subspecies maritima); Massachusetts, United States.
Example of Seaside Sparrow breeding habitat in Massachusetts.

In Massachusetts, high marshes, medium-height S. alterniflora is widespread, growing on the edges of creeks and ditches, thus providing a variety of foraging microhabitats.

Bird in its breeding habitat (subspecies mirabilis); Florida, United States.
Example of Seaside Sparrow overwintering habitat in South Carolina.

Resident Seaside Sparrows in South Carolina regularly winter in tall S. alterniflora growing in the intertidal zone along creeks and bay edges near nesting areas.

Adult with insects for nestlings.
Bird with crab.
Bird feeding on cracked corn.
Bird carrying an insect.
Bird feeding on marine annelid.

Feeds mainly in open stands of grass, shallow pools, and pannes. Most common foraging mode is walking on ground, gleaning arthropods from surrounding vegetation, usually by attacking prey that can be reached by extending neck or by lunging short distances. Individuals walking on ground also probe and peck mud or whatever surface they are walking on.

Feeding on arthropod.
Adult with insect for nestlings (subspecies maritima); New York, United States.
Seaside Sparrow performing flight song display.

Wingbeat rapid and regular during ascent of flight (song) display, but at apogee of display, wings set slightly above horizontal, and bird briefly glides diagonally downward uttering one or more Primary Songs.

Seaside Sparrow bathing.

Bathing involves repeatedly submerging the ventral surface and dipping the head, following by shaking and fluttering feathers.

Nest with its natural concealment by Spartina grass.
Nest; general view.
Adult carrying nest material.
Nest with four eggs.
Seaside Sparrow nest. 

Nest is a cup of grass stems and blades, lined with finer grass blades. Specimen collected: Beach Haven, New Jersey. 13 June 1920; photographer Rene Corado.

Seaside Sparrow clutch.

Egg ground color is bluish white to grayish white, speckled and blotched with shades of brown, often more heavily on larger end. Specimen collected: Cape May County, New Jersey. 10 July; photographer Rene Corado.

Clutch of two eggs.
Nest with one egg and one hatchling.
Chicks at nest begging for food.
Adult with food for nestlings.
Group of juveniles perched on the grass; June, North Carolina, United States.

Fledglings and juveniles gather in loose groups. One or more adults, as well as Saltmarsh Sparrows, may join groups.

Macaulay Library Photos for Seaside Sparrow

Top-rated photos submitted to the Macaulay Library via eBird. Note: Our content editors have not confirmed the species identification for these photos.

Recommended Citation

Greenlaw, J. S., W. G. Shriver, and W. Post (2022). Seaside Sparrow (Ammospiza maritima), version 2.0. In Birds of the World (P. G. Rodewald and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.seaspa.02