- 5.1–5.9 in
- 7.1–7.9 in
- 0.7–1 oz
- Although territorial, the Seaside Sparrow often feeds long distances from the space it defends around its nest. In the tidal zone where it lives, nesting and feeding areas often are widely separated.
- The Seaside Sparrow is divided into several different subspecies that look subtly different. The two most distinct forms, the endangered "Cape Sable" Seaside Sparrow and the extinct "Dusky" Seaside Sparrow were once considered separate species. The "Cape Sable" Seaside Sparrow has dark streaks on a white chest and is the palest form. The "Dusky" Seaside Sparrow was the darkest form, with a blackish back and heavy dark chest streaks.
- The oldest recorded Seaside Sparrow was a male, and at least 10 years old when he was recaptured and rereleased during banding operations in South Carolina.
Salt marshes, especially spartina grass, rushes, and tidal reeds; "Cape Sable" Seaside Sparrow in marsh prairie.
Seeds, insects, spiders, marine invertebrates.
- Clutch Size
- 2–5 eggs
- Egg Description
- Bluish white to grayish white, speckled and blotched with shades of brown, often more heavily on larger end.
- Condition at Hatching
Open cup of grass stems and blades, lined with finer grass blades and sometimes built up on sides to form partial covering.
Walks on ground and gleans prey from surrounding vegetation; probes with bill in mud.
Seaside Sparrow are common overall, most populations were stable between 1966 and 2014, according to the North American Breeding Bird Survey. Other populations are declining and vulnerable. Partners in Flight estimates a global breeding population of 160,000, with 100% living in the U.S. The species rates a 13 out of 20 on the Continental Concern Score. The Cape Sable population of Seaside Sparrow in southern Florida is endangered and is on the 2014 State of the Birds Watch List, which lists bird species that are at risk of becoming threatened or endangered without conservation action. "Dusky" Seaside Sparrow went extinct in the 1980s.
- Post, W., and J. S. Greenlaw. 1994. Seaside Sparrow (Ammodramus maritimus). In The Birds of North America, No. 127 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologistsâ€™ Union.
- North American Bird Conservation Initiative, U.S. Committee. 2014. State of the Birds 2014 Report. U.S. Department of Interior, Washington, DC.
- Partners in Flight. 2012. Species assessment database.
- U.S. Fish & Wildlife Service, ECOS-Environmental Conservation Online System, Cape Sable Seaside sparrow (Ammodramus maritimus mirabilis).
- U.S. Fish & Wildlife Service, ECOS-Environmental Conservation Online System, Dusky Seaside sparrow (Ammodramus maritimus nigrescens).
- USGS Patuxent Wildlife Research Center. 2015. Longevity records of North American Birds.
- USGS Patuxent Wildlife Research Center. 2014. North American Breeding Bird Survey 1966–2014 Analysis.