The seaside sparrow, which has but one molt each year, forages in relatively open areas.
The chase of the seaside sparrow is not vigorous, but in all cases the intruder was seen to give way to the defender.
Type A (mating, nesting, and feeding ground for young) is the type exhibited by the seaside sparrow.
A seaside sparrow that I watched for one hour sang 395 times or 6.6 times per minute.
The seaside sparrow nests in marsh-elder bushes, or in areas of mixed vegetation.
Song of the seaside sparrow functions importantly in the establishment and maintenance of its territory.
The nestlings of the seaside sparrow are fed by both parents.
In the seaside sparrow a complete post-juvenal molt begins in late August.
Four of the eight seaside sparrow nests I found contained at least three eggs, and four contained at least four eggs.
The seaside sparrow has only a postnuptial molt, the nuptial plumage being acquired by wear.