The alarm call of the Sharp-tailed Sparrow is not so loud as that of the Seaside Sparrow and it is not given so often. I described it as a short _tsick_ or _tsuck_. Females emitted such calls when I was at their nests or when male Sharp-tailed Sparrows came near their nests. Males may have a similar call, but I never recorded it. Montagna (1942a:116) remarks on the quietness of this species. This is especially evident when one compares Sharp-tailed Sparrows with Seaside Sparrows. PLATE 1 [Illustration: FIG. _a_. An aerial photograph of the Lavallette study island. One inch equals approximately 375 feet. The area covered by sand has been extended since this photograph was taken. This is indicated in figure _b_ of this plate.] [Illustration: FIG. _b_. Map of the Lavallette study island. All fringillid nests that I found are indicated and the territorial boundaries of the Seaside Sparrows are shown. [triangle]--Seaside Sparrow [dot]--Sharp-tailed Sparrow [star]--Song Sparrow] PLATE 2 [Illustration: FIG. _a_. The south shore of the Lavallette study island showing the two major driftlines and the sparsely vegetated areas. This is the feeding habitat of the Seaside Sparrow.] [Illustration: FIG. _b_. A close-up view of a segment of the shoreline. Note the spacing of the clumps of cord-grass (_Spartina alterniflora_). A six inch ruler propped against a 12 inch stick is included to indicate the size and spacing of the plants.] PLATE 3 [Illustration: FIG. _a_. The inner portion of the marsh on the Lavallette study island showing the rows of marsh-elder bushes (_Iva frutescens_) and the extensive areas of black grass (_Juncus gerardi_). Areas of mixed black grass and cord-grass appear in the foreground. All the nests of Sharp-tailed Sparrows were found in the areas of black grass. Four of the eight nests of Seaside Sparrows were in the marsh-elder. One of the blinds that I used is shown in this photograph.] [Illustration: FIG. _b_. A mated, banded pair of Seaside Sparrows in a dead marsh-elder bush near their nest. Note the abdomen of a moth protruding from the bill of the female on the right.] PLATE 4 [Illustration: FIG. _a_. A female Sharp-tailed Sparrow at the entrance to her nest. The throat on this bird is dark because of dye applied by me.] [Illustration: FIG. _b_. The nest of a Sharp-tailed Sparrow viewed from above. Stems of black grass were parted to take the picture. The outer rim of this nest (lower right) is made of living stems of black grass.] COPULATION