Adult Henslow’s sparrow upperparts are dark brown with black and tan streaks. There is a greenish-gray tint to eyebrow and nape. Crown is dark, with a white central crown stripe and a dark brown, incomplete edge to the greenish cheek. The forehead is low, creating a flat-headed profile with the large bill. Underparts are white, with two dark streaks extending down the neck from the bill and dark streaking on the upper breast. Juveniles lack streaks in the center of the breast. A short-tailed and weak-flying species. Song is an insectlike tsi-lick, or seealick.
Similar species: Sparrow IDs can be tricky. In this case, consider the habitat. Here are two other sparrows to look for in Missouri’s prairies: Grasshopper sparrow has tan cheeks and clear buff underparts, with no streaks on the neck. Le Conte’s sparrow is rarely seen here in summer; it has a broad, orange-buff eyebrow. Dickcissels are somewhat sparrowlike and can be common in prairies, too.
Length: 5 inches (tip of bill to tip of tail).
Possible to see statewide, but most likely to be seen in our southwestern prairies.
Habitat and Conservation
Prairies, moist grasslands, alfalfa fields, and weedy fields. Like the Le Conte’s sparrow, it is shy, reluctant to fly, and requires some effort to get a good look. Listen for its song at dusk and dawn; it sometimes sings at night, too. Compared to the grasshopper sparrow, Henslow’s is more likely to be found in less dry, medium-high to tall grasslands with a 2–3 year accumulation of grass thatch from previous growing seasons. Prefers native prairie and diverse, nonfescue grasslands.
Food
Forages on the ground, often under grass litter, for seeds and insects.
Status
As a summer resident, uncommon and local in southwestern Missouri; rare in the north. In many areas, Henslow’s sparrow populations are declining, undoubtedly because of shrinking grassland habitat. Seven states have declared it endangered within their borders. Conservation organizations and government agencies are working to establish grassland areas large enough to support this and many other prairie species, such as the greater prairie-chicken.
Life Cycle
Henslow’s sparrows start arriving here in mid-April. Bowl-shaped nests are constructed of dry grasses, built over the ground on a clump of grass. A clutch comprises 2–5 eggs. In the first half of September, southward migration begins; they are all gone from Missouri by the end of October. The wintering range extends from eastern Texas to the southern tip of North Carolina. Birds that eat seeds off the ground cannot tolerate much snow cover.
Human Connections
People tend to like challenges and appreciate the rare. Birders seek out this shy bird with the flat-looking, olive-green head, traveling to our few remaining tallgrass prairies and getting up before dawn to listen for its simple, easy to overlook, yet distinctive, insectlike song.
Ecosystem Connections
Tallgrass prairies support a staggering diversity of plants and animals, even within a small section of land. In the past, the central United States was a sea of prairie, but today it’s a sea of agriculture. Henslow’s sparrow is part of the glorious diversity supported in our native grasslands.
About 350 species of birds are likely to be seen in Missouri, though nearly 400 have been recorded within our borders. Most people know a bird when they see one — it has feathers, wings, and a bill. Birds are warm-blooded, and most species can fly. Many migrate hundreds or thousands of miles. Birds lay hard-shelled eggs (often in a nest), and the parents care for the young. Many communicate with songs and calls.