Henslow's Sparrow, Ammodramus henslowii
The Henslow's Sparrow's secretive nature makes identify its song extremely important when trying to find this small grassland bird. The male Henslow's will stand on a low perch, throw his head back, and belt out, what sounds like, a hiccup!
Its breeding habitat includes overgrown fields and meadows, often wet, with scattered low shrubs or saplings and standing dead vegetation from the previous season. The breeding range extends from the north-central United States eastward, and south to Kentucky and northern Virginia. It appears to have extended its breeding range into central Tennessee starting in the late 1990s. In winter, Henslow's Sparrow migrates to marshes and open pinewoods in the southeastern United States. Range-wide the species has been declining at an estimated 7.5% per year, primarily due to loss of breeding habitat.
This species can be found In Tennessee from mid-April until late October, and while it was listed as In-Need-of-Management in Tennessee in 2000, it appears to be increasing as a breeding bird in the state.
Description: The Henslow's Sparrow is a small, relatively large headed, short-tailed songbird that has dark brown streaked upperparts, a light brown sparsely streaked breast, a white throat and belly, an olive-green nape, two stripes on the lower face, and rust-colored wings. Juveniles (June-August) look similar to adults, but have more indistinct markings on the head and reduced streaking across the chest. Males and females look similar.
Weight: 0.46 oz
Voice: The song has been described as sounding like a hiccup, or a dry tsi-zleik. Henslow's sometimes sing on quiet nights.
- Le Conte's Sparrow has a bright buffy color on head, and the nape is gray streaked with purple (not olive-green).
- Grasshopper Sparrow has an unmarked buffy breast.
Habitat: Breeding habitat includes large, flat, overgrown, moist fields, with scattered low shrubs or saplings, some standing dead vegetation from the previous season, and a deep litter layer. Henslow's are also found in native warm season grass fields, typically one year or more since burning, and unmowed hayfields.
Diet: Insects, mostly grasshoppers and beetles.
Nesting and reproduction: Henslow's often nest in small loose colonies, and frequently raise two broods of young per breeding season
Clutch Size: Ranges from 3 to 5 eggs, with 4 most common.
Incubation: The female alone incubates the eggs for about 11 days.
Fledging: The female does most of the feeding, and the young fledge in about 9 or 10 days.
Nest: It takes the female 5 or 6 days to build the well-concealed open-cup nest placed at the base of a grass tuft (usually) or up to 16 inches in the vegetation. The nest is constructed of loosely woven dry grasses.
Status in Tennessee: The Henslow's Sparrow is a rare migrant and recent breeding bird in Tennessee. It appears to have extended its breeding range into the state in the late 1990s, and was listed as In-need-of-management in 2000. The Henslow's Sparrow has been identified as a species of the highest priority for grassland bird conservation in eastern and mid-western North America by Partners in Flight (PIF), a cooperative effort of many organizations dedicated to bird conservation. This species can be found In Tennessee from mid-April until late October.
- John James Audubon first discovered the Henslow's Sparrow in 1820 in Kentucky. He named the bird in 1831 in honor of John Stevens Henslow (1796 to 1861), British botanist and geologist, clergyman, and mentor to Charles Darwin.
- Henslow's Sparrow will sometimes sing at night, especially when the moon is very bright, but usually sings most actively at dawn and dusk.
- Rather than fly, the Henslow's Sparrow runs away through the grass when threatened.
- Historically Henslow's Sparrows were concentrated in two areas: the central prairies of the United States and the coastal marshes of the Atlantic Coast. As the intervening forests were cut down, they moved into the newly created grasslands, connecting the two centers of distribution. Henslow's are rarely found in coastal marshes today.
- The Bird Banding Lab web site reports that between 1955 and 1997, a total of 900 Henslow's Sparrows were banded. Of these, only 3 have ever been recovered, a very low recovery rate of 0.033%.
Herkert, J. R., P. D. Vickery, and D. E. Kroodsma. 2002. Henslow's Sparrow (Ammodramus henslowii). The Birds of North America. No. 672 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA., and The American Ornithologists' Union, Washington, D.C.
Nicholson, C. P. 1997. Atlas of Breeding Birds of Tennessee. Univ. Tennessee Press, Knoxville.
Sibley, D. A. 2000. The Sibley Guide to Birds. A. A. Knopf, New York, NY.