The Henslow's Sparrow is a species of bird whose population has steadily declined for several decades because of habitat loss in Kentucky and other states where it spends its breeding season. At Land Between the Lakes National Recreation Area, preservation efforts make room for the little songbird and other native species.
According to the U.S. Fish and Wildlife Service Migratory Bird Program's Web page on the bird, habitat loss is the primary reason for a breeding population decline estimated at an average of 7.5 percent annually since the mid-1960s. These "moderately rapid population declines" are why the International Union for Conservation of Nature classifies the Henslow's Sparrow as "Near Threatened" on its Red List of Threatened Species.
The Rocky Mountain Bird Observatory lists the estimated population of the Henslow's Sparrow at 400,000: far less than, say, the Song Sparrow, whose population is estimated at 75 million and is characterized on its National Audubon Society Web page as "one of the most widespread, diverse, and geographically variable of North American birds."
The breeding habitat of the small, well camouflaged Henslow's Sparrow â described by the National Audubon Society's online listing as five inches long with a six and a half-inch wingspan, weighing less than half an ounce â typically consists of large, moist fields â between 50 and 200 acres or so â of tall native grasses and plants with few trees or other woody plants.
The bird builds its nests on top of dense vegetation just above the ground's surface. Mow down the native grass and clear out the field and, U.S. Forest Service Wildlife Biologist Elizabeth Raikes said, "You've essentially wiped out their habitat."
Raikes, who works at Land Between the Lakes, said the bird's breeding range includes parts of Kentucky, Tennessee and numerous other states to the north across the eastern United States. But habitat loss has been a problem across the range because of agriculture and commercial development.
In Kentucky specifically, Raikes said the sparrow's ideal habitat has been more or less eliminated because grasslands have been converted into croplands and hayfields.
One place in western Kentucky where the bird's preferred habitat remains is Land Between the Lakes, which includes some large areas of grassland it has maintained over several years. Raikes said the Henslow's Sparrow has been observed in LBL's Crossroads Area â in the upper northeast portion of the park â as well as in the northwest corner of the Brandon Spring Group Center to the south and in the Elk and Bison Prairie.
A variety of methods are used to maintain grasslands at LBL. Mulchers and other large equipment are used to clear out trees and other woody plants to make room for the grasses to grow. The areas also have to be disturbed every two to three years, Raikes explained, to control non-native invasive plants and other unwanted species. Methods of periodic disturbance include prescribed fire, mowing and the use of herbicide.
The National Wild Turkey Federation is among the partners that helps LBL maintain grassland areas. Jason Lupardus, NWTF's regional biologist for Kentucky and Tennessee, said the federation is doing some restoration work in LBL this month, including in the Crossroads Area.
Lupardus has been involved with restoration efforts at LBL for a number of years, and said those efforts have made a noticeable difference in the number of birds in the Crossroads Area.
"If you could have been there three years ago, and see it now and hear the plethora of birds chirping away â including the Henslow's â it's good stuff," Lupardus said.
Those areas of grassland are not preserved specifically for the Henslow's Sparrow, but for a variety of native plant and animal species that live there. However, when the bird showed up in an unexpected part of the national recreation area, efforts were made to accommodate the feathered guest.
In the spring of 2009 Raikes heard the sparrow's short, unassuming "tsi-lick" call in three small hayfields in the Barnes Hollow area totaling about 30 acres of land â an area much smaller than the bird's typical habitat.
"I was surprised that we've observed it in...hayfields, because it's less than ideal conditions," Raikes said. "But this bird is using less than ideal conditions than have been previously observed to sustain itself."
The fields were being used by a farmer who had a permit to cut hay there. Working with the farmer, in 2009 LBL reserved 15 of those 30 acres for the bird to nest and the other 15 for the farmer to cut hay in, rotating out periodically. Raikes said now, about five years later, LBL continues to observe the Henslow's Sparrow on those 15 acres.
"That's a component of our landscape that doesn't exist much anymore," Raikes said of the grassland areas, adding that the native grasses and weeds on the 15 acres set aside specifically because of the Henslow's Sparrow, for example, also benefit pollinator species â such as dragonflies, bees and hummingbirds â spiders, butterflies and small mammals â like shrews and voles â that provide food for other species on the food chain. The grasslands are also ideal for the bobwhite quail â another Near Threatened bird on the IUCN Red List of Threatened Species â which Raikes said has been observed in the Crossroads Area.
For more information on Land Between the Lakes, visit http://lbl.org.
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