Numbers, movements, and habitat of the Dusky Seaside Sparrow (Ammospiza maritima nigrescens) were investigated during 1972-1973 on the newly established St. Johns National Wildlife Refuge. Numbers declined from 110 males in 1972 to 54 in 1973. This decrease was probably due to 2 winter wildfires. Observations of banded individuals indicated that the bird is generally sedentary throughout the year and that preferred winter habitat is similar to breeding habitat. Cordgrass (Spartina bakerii), with a mean percent cover of 38.1±16.3, was dominant over the 22 other plant species on the territories. Cover mapping showed that although 20 percent of the refuge had preferred vegetation types, only about 10 percent (400 acres) was actually available as preferred habitat.