The Seaside Sparrow eats mainly insects and other invertebrates and (especially in fall and winter) seeds.
The Seaside Sparrow forages on the ground and in low vegetation at the water's edge (Kaufman 1996).
The Seaside Sparrow (Ammodramus maritimus) breeds from southern New Hampshire and Massachusetts (U.S.A.) south along the Atlantic coast to Florida and along the Gulf coast from Florida to Texas. It is closely tied to salt marshes--more so than any other North American songbird. With the exception of a few Florida populations, it is nearly always found in association with tidal marshes right along the coast. (Kaufman 1996; AOU 1998)
The last known individual of the form known as the Dusky Seaside Sparrow (from Brevard County, Florida) died in 1987 (see Zink and Kale 1995 for a discussion of the last ditch efforts to save this bird through captive breeding). The Cape Sable form of extreme southern Florida is listed as endangered under the U.S. Endangered Species Act (e.g., USFWS 1999).
The Seaside Sparrow breeds from southern New Hampshire and Massachusetts south along the Atlantic coast to northeastern Florida (south to the St. Johns River, formerly to New Smyrna Beach) and along the Gulf coast from western Florida (south to Tampa Bay) west to southeastern Texas (south to Corpus Christi area). The winter range extends south along the Atlantic coast from Massachusetts through the remainder of the breeding range (casually to southern Florida) and along the Gulf Coast throughout the breeding range and south to the mouth of the Rio Grande. The recently extinct form known as the Dusky Seaside Sparrow was resident along the coast of east-central Florida (eastern Orange and northern Brevard counties). The form known as Cape Sable Seaside Sparrow is resident in extreme southern Florida (southwestern Collier, Monroe, and southern Dade counties). (AOU 1998)
The Seaside Sparrow inhabits coastal tidal marshes. In Florida, the now extinct form known as the Dusky Seaside Sparrow nested in fresh or brackish marshes in some areas; in parts of extreme southern Florida, the Cape Sable Seaside Sparrow still does so. (Kaufman 1996)
In non-migratory southern populations of the Seaside Sparrow, members of a pair may stay together on the nesting territory year-round. The nest, which is built by the female alone, is constructed in marsh vegetation just a few inches above the highest tides. Three to four eggs are typical (range two to five). The eggs are bluish white to pale gray and incubation (by female only) is 12 to 13 days. Both parents feed young. Young leave the nest 9 to 11 days after hatching, but cannot fly for another week or so. After fledging, young may continue to be fed by their parents for several weeks. (Kaufman 1996)
Hill and Post (2005) used genetic markers to estimate the prevalence of extra-pair paternity in a population of Seaside Sparrows in South Carolina. They concluded that about 11% of chicks were sired by a male other than the (behaviorally) putative father and that these chicks occurred in just 17% of the broods studied. This is an unusually low rate of extra-pair fertilization based on comparison with related species.
As a result of the patchy distribution of its habitat, several forms of Seaside Sparrow with distinctive appearance evolved in relative isolation. One, the Cape Sable Seaside Sparrow, was not discovered until 1918; another, the Dusky Seaside Sparrow, became extinct in the late 1980s despite extreme (if belated) conservation efforts. (Kaufman 1996)
The Seaside Sparrow is threatened by ongoing destruction of its coastal marsh habitat, which led to the destruction of the form known as the Dusky Seaside Sparrow in the late 1980s. (Kaufman 1996)
