Vesper sparrow

Distribution and Habitat

Locally, the vesper sparrow breeds in the inner coastal plan of South Jersey and the Piedmont, Highlands, and Ridge and Valley regions of northern and central New Jersey. Nesting is concentrated in the north-west of the state, throughout most of New Jersey.

Vesper sparrows are rare fall migrants in New Jersey, occurring from mid-October to mid-November, with an average of ten records each fall at Cape May Point. Vesper sparrows rarely over-winter along the southern coastal region of New Jersey. The vesper sparrow is an extremely rare spring migrant. Spring migrants occur from early April to mid-May.

Vesper sparrows reside in cultivated fields, grasslands, and pastures. Farmed areas that are adjacent to fallow fields or contain uncultivated strips along fence-rows are favored. These fallow areas provide nesting habitat, cover, foraging sites, and singing perches. On active farmlands, human disturbance and crop harvesting can threaten nesting sparrows. Fallow fields and grasslands provide a safer haven for nests.

Vesper sparrow habitats are typically sparsely vegetated with patches of bare ground, low vegetation and scattered shrubs. Habitats are typically dry and well drained. Nests are placed within clumps of cover that afford protection from predators. Elevated perches, such as fence posts provide singing posts from which males can advertise their territories and attract mates. Territory size may range from 1.2 to 7.9 acres. Similar habitats are used throughout the year.

Diet

The diet of the vesper sparrow consists of invertebrates and seeds. During the summer months, the diet consists largely of invertebrates such as beetles, grasshoppers and other insects. Weed and grass seeds are also consumed during this time, although in a smaller proportion. Young sparrows are fed invertebrates almost exclusively. Vesper sparrows are a beneficial species in agricultural areas, as they consume many crop-destroying insects. In the fall and winter, seeds of various plants are sought. Vesper sparrows forage on the ground in weedy fields, brushy edges, and recently mowed fields.

Life Cycle

During April, male vesper sparrows arrive on their breeding grounds and establish territories. About a week later, the females return. Vesper sparrows exhibit site fidelity, as pairs return to the same nesting location during consecutive years. They often form small colonies, with three to six pairs nesting in an area.

Over a one- to two-week period, the female vesper sparrow constructs a cup nest of grasses, and lines it with thinner grasses. The ground nest often is concealed in a hollow at the base of a weed or grass tuft.

By the second or third week of May, the female lays a clutch of three to five greenish white eggs that are blotched with brown. Both parents, although primarily the female incubate the eggs for 11 to 13 days. The protective incubating adult will not flush from the nest until nearly stepped upon, at which time it will feign injury to lure an intruder away. At 9 to 13 days, the chicks, not yet independent, leave the nest. The adults continue to care for the young, which seek cover in the surrounding vegetation, for several weeks. If a pair produces a second clutch, the male will tend to the first brood while the female begins incubating the subsequent clutch.