Grasshopper Sparrow

The Grasshopper Sparrow, scientifically known as Ammodramus savannarum, is a diminutive member of the New World sparrow family. This species exhibits a streaked brown, grey, black, and white upper body, with a lighter brown breast and a white belly. The tail is short and brown. A distinctive feature is the bright yellow feathers at the bend of the wing and above the lores. Both sexes are similar in plumage, and juveniles quickly molt into adult plumage within months of fledging.

Identification Tips

When identifying the Grasshopper Sparrow, look for the light brown face with a white eye ring and a dark brown crown with a central narrow light stripe. The presence of yellow-to-amber patches above the lores and underwing coverts are key distinguishing marks. Adults typically measure 10–14 cm in length, with a wingspan of approximately 17.5 cm, and weigh between 13.8 to 28.4 grams.

Habitat

Grasshopper Sparrows favor open fields and prairie grasslands, often with a patchy distribution of vegetation that includes areas of bare ground for foraging and denser clumps for nesting concealment. They tend to avoid trees and shrubs, preferring heterogenous patches of prairie.

Distribution

This species is widely distributed across southern Canada, the United States, Mexico, Central America, and the Caribbean. There is also a small, endangered population in the Andes of Colombia.

Behaviour

Grasshopper Sparrows exhibit a high degree of movement, including annual migrations and frequent dispersal between breeding attempts or seasons. They are known to be socially monogamous, with a tendency for high rates of extra-pair mating. Breeding pairs can raise multiple broods, with the number of broods varying by geographic location.

Song & Calls

The Grasshopper Sparrow's primary song is a high trill preceded by a series of short chips, reminiscent of grasshopper sounds, hence the species' name. They also have an alternate song, male and female trills, and a call/chip note. The primary song is used for territory defense and mate attraction, while the alternate song is associated with pair bonding.

Breeding

Nests are dome-shaped, well-concealed on the ground, and constructed by females. Clutch size typically ranges from 4-5 eggs, with incubation lasting 10-12 days and nestlings fledging after 6-9 days. The species is known to suffer from brood parasitism by the Brown-headed Cowbird.

Similar Species

The Grasshopper Sparrow can be confused with other sparrows, but its unique song and yellow markings help distinguish it from similar species.

Diet and Feeding

The diet consists mainly of insects, especially grasshoppers, spiders, and seeds. Foraging occurs on the ground in areas of sparse vegetation.

Conservation status

The Grasshopper Sparrow is currently classified as Least Concern by the IUCN, despite a steep decline in populations, particularly in the tallgrass prairies of the central Great Plains. The Florida subspecies, Ammodramus savannarum floridanus, is highly endangered.

Habitat Management

Conservation efforts for the Grasshopper Sparrow focus on maintaining and managing grassland habitats, including moderate grazing and prescribed burning to prevent shrub encroachment and maintain the open habitats this species requires.