Seaside Sparrow Identification, All About Birds, Cornell Lab of Ornithology

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.

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)

Found in tidal marshes with dense areas of marsh grass. Sings a soft buzzing song that sounds like a distant Red-winged Blackbird.

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.

Habitat

Breeds in tidal marshes.

Adult (Gulf of Mexico)

Gulf of Mexico populations have obvious streaking on the back and a buffy chest with dark streaks.

Adult (Atlantic)

Medium-sized sparrow with a long bill. Atlantic populations have a grayish belly with indistinct streaking and a yellow stripe in front of the eye. Note rusty wing patch.