From the Michigan Audubon Society
The Henslow’s Sparrow is Michigan’s smallest species of sparrows measuring only four to five inches long and weighing no more than half of an ounce. The Henslow’s Sparrow is a grassland bird that blends to its surroundings well, with streaks of brown, olive and chestnut to mimic the tall grass it calls home. It is also a Michigan Endangered species.
John James Audubon discovered the species in Kentucky in 1820 and named the sparrow in honor of John Stevens Henslow, a close friend and botanist at Cambridge University and professor to Charles Darwin. The Henslow’s Sparrow was not documented in Michigan until 1881 and was uncommon in the early 1900s.
Population numbers increased during the early part of the last century; woodlots and forests were cleared, which grew into large open grasslands, providing suitable cover and abundant food for the sparrows. The first observation of the sparrow in the Upper Peninsula did not come until 1959. Today, the Henslow’s Sparrow has been observed in 36 counties in Michigan.
Unfortunately, the last decade has shown a large population decline in Michigan and all over the Midwest. Kalamazoo County has reported an 80 percent decline in population numbers since 1970. This trend is largely due to rapid decreases in the amount of suitable habitat. Livestock grazing and early hay harvests have decreased the size and value of breeding grounds along with the encroachment of woody vegetation. Urbanization of small grassland parcels and the reduction or exclusion of fire management practices has also diminished the sparrow’s habitat.
Management techniques used to bring back and stabilize the sparrow’s population numbers include prescribed burning, scheduled mowing after the breeding season and monitored grazing to ensure vegetation remains adequately tall and dense. Ornithologists also recommend providing 75 acres or more of contiguous grassland to allow for colonization of the Henslow’s Sparrows. Lastly, limiting or restricting the use of insecticidal applications will provide better food resources for the Henslow’s Sparrow, who feeds exclusively on insects.
These management techniques also benefit Ring‐necked Pheasants and the hunters that pursue them each fall. Mike Parker, a Michigan DNR Wildlife Biologist and former Pheasant Forever representative, has spent several years working to improve grassland habitats in Michigan and agrees that improving habitat for one species greatly benefits the other. Parker also suggests that private landowners can help conserve both species by landscaping their property to include high quality grassland habitats.
“The great news is there are a variety of programs available to landowners from the Michigan DNR, US Department of Agriculture, US Fish and Wildlife Service and other partners [such as Michigan Audubon] that can provide funding or technical assistance to restore grassland habitat that is beneficial to pheasants,
sparrows and a diversity of other grassland birds.”
The Henslow’s Sparrow is a shy and elusive bird that is usually heard rather than seen. “It takes a really keen birder to be able to find the Henslow’s Sparrow”, states Tom Funke, Michigan Audubon’s Conservation Director. “Often, the bird is shown to birders by someone else“, says Funke, “as this bird is very hard to see and hear. You just don’t stumble upon this rare bird.”
Michigan Audubon has three sanctuaries were the Henslow’s Sparrow has been observed in recent years: the Mildred Harris Sanctuary in Alamo Township in Kalamazoo County; the Phyllis Haehnle Memorial Sanctuary in
Leoni Township in Jackson County; and at the Otis Farm Bird Sanctuary in Hastings in Barry County. Michigan Audubon holds an annual event at the Otis Sanctuary, Cerulean Warbler Weekend May 31 thru June 2, where the Henslow’s Sparrow is a featured species. The Otis Sanctuary is a globally recognized Important Bird Area for the Henslow’s Sparrow.