Henslow’s Sparrow (HESP)

Centronyx henslowii

Adult Henslow’s Sparrow  © Ryan Sanderson / Macaulay Library
Juvenile Henslow’s Sparrow © Mark Brown / Macaulay Library

Range

The Henslow’s Sparrow breeds in several states, including Minnesota, Wisconsin, Michigan, New York, Nebraska, Kansas, Oklahoma, Iowa, Missouri, Arkansas, Illinois, Indiana, Ohio, Kentucky, West Virginia, Pennsylvania, Maryland, North Carolina, and Virginia. It is now rare or extirpated in northeastern U.S. states. During the winter, the species mainly inhabits the southeastern U.S., and it has been sporadically sighted in more northern regions like Wisconsin, Illinois, Indiana, and New England.

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Identification

The Henslow’s Sparrow is characterized by a large, flat-topped head, a large, heavy bill, and a short, pointed tail. It has dark coloration with olive-green to buffy-olive wash on the head, dark chestnut patterned upperparts, and narrow blackish streaks across the buffy breast and flanks, while the rest of the underparts are whitish. The sexes look alike, with the only difference being in the juvenile plumage, which has weaker facial markings, reduced streaking on the underparts, and pale fringes on the back and scapulars, creating a scalloped effect.

Henslow’s Sparrows are elusive birds that spend much of their time on the ground. They are often spotted sitting just below the tops of grass stalks and small shrubs, resembling a cluster of grass seeds. When faced with threats, they prefer running through the grass rather than taking flight. During the breeding season, males sing from exposed perches, making them easier to observe, but they are generally secretive and hard to find in other seasons. The Henslow’s Sparrow has the simplest and shortest song of any North American songbird, described as a “buzzed tzelick” to the human ear. They are most active in singing at dawn and dusk and sometimes sing all night long. Additionally, they have an alarm called “tsip” and produce a series of high-pitched whistles during the breeding season.

Listen to its songs and calls here.

Habitat

Henslow’s Sparrows breed in diverse habitats, including wet meadows, weedy pastures, and lowland prairies, and they have a historical presence in Atlantic coastal marshes, swamps, and dry fields. Nowadays, Henslow’s Sparrows have also adapted to cultivated hayfields, typically mowed in mid-late summer after young have fledged, and reclaimed surfaces in western Pennsylvania, southern Ohio, Kentucky, and southwestern Indiana. In general, their habitat can be characterized as relatively large fields consisting of tall, dense grass, a well-developed litter layer, standing dead vegetation, and sparse or no woody vegetation.  The wintering habitat of Henslow’s Sparrows closely resembles their breeding grounds, characterized by an abundance of dense groundcover. General descriptions of the overwintering grounds frequently refer to a preference for open, boggy pine flats, grassy pine flats, or low moist areas.

Conservation Status 

Status by State

Threats to Conservation

Populations of Henslow’s Sparrow are declining sharply, possibly due to the use of pesticides and the destruction of native grasslands. However, the loss of proper breeding habitat appears to be the main cause of this decline. Activities such as fire suppression, conversion of pasture to agriculture, frequent and early cutting of hayfields, and wetland drainage are contributing to the loss of suitable breeding habitat. Urbanization is also cited as a reason for the species’ decline. Primary threats on the overwintering grounds include exclusion of or reduction in frequency of fire, drainage, urbanization, and conversion to agriculture or pine plantations.

Funding Opportunities
General Management Guides
Regional Management Guides
Northeast
Midwest & Central
Resources
Works Cited