Across the US, grassland birds have seen the greatest declines of any bird group. Most of the decline can be tied directly to habitat loss. First the prairie was tilled, causing great reductions in populations. More recently, the conversion of pastures to row-crop agriculture has reduced populations further. Prairie restorations are quickly becoming refuges for this group of birds.
Many grassland birds require large, open grasslands to breed. Small grasslands only capture a subset of species. Large restorations, like the Conservancy’s Kankakee Sands and Glacial Ridge, as well as the US Forest Service’s Midewin Tallgrass Prairie, are big enough to attract most species, and in very large numbers.
Summer breeding species include the threatened Henslow’s sparrow, grasshopper sparrow, savannah sparrow, sedge wren, upland sandpiper, and many more. Some species, like the field sparrow, fly up from the southern US to breed in Indiana. Other species, such as the bobolink, fly from as far away as Argentina each summer.
Grassland birds need open, treeless expanses, as the name implies. But species have different tastes when it comes to prairie. Some, like the bobolink and Henslow’s sparrow, like dense vegetation that is fairly tall. They will avoid lesser cover. Other species, like the grasshopper sparrow and upland sandpiper, look for very short vegetation. Some like it wetter, some like it drier.
Using the habitat guidelines established by bird researchers, we have designed some of our prairie plantings to match the structural needs of grassland birds. Some plantings have tall vegetation, some very short, some wet and some dry. We have been able to create short-structure plantings using short-stature grasses and forbs, thereby avoiding the need for mowing or other mechanical means to keep the prairie short. We have designed sedge meadows that provide excellent habitat for birds like the sedge wren.
Wet prairies provide excellent stopover habitat for migrating shorebirds and waterfowl. They also provide good breeding habitat for marsh birds, such as rails, egrets, and cranes. Kankakee Sands is an important stopover sight for a variety of shorebirds that use our shallow wetlands to rest and feed before flying onward to their breeding grounds. Some rare species we have seen – the piping plover (5 individuals from the 50 bird Great Lakes flock), the black and yellow rails, and the Wilson’s phalarope. Common breeding species include the American bittern, the sora, and the sedge wren.
Birds that prefer shrubby cover have also found a place at Kankakee Sands. Pockets of willows and dogwood provide excellent cover for these birds. From the common indigo buntings, field sparrows, and to the rarer yellow-breasted chat, black-billed cuckoo and Bell’s vireo, native shrubs patches have created a haven for these species. Nearby Willow Slough Fish and Wildlife Area is a regional stronghold for shrubland birds.
Winter is a great time to see migrating hawks. Northern harriers and rough-legged hawks are extremely common at Kankakee Sands. Short-eared owls also frequent the prairie during late winter and early spring.
National Trends on Grassland Birds
A recent National Audubon Society study, The State of the Birds, found that 70 percent of grassland bird species are experiencing significant declines.
Four of the 25 fastest declining bird species in North America breed in the prairie and wetlands at Kankakee Sands:
Henslow’s sparrow (No. 3),
grasshopper sparrow (No. 20),
field sparrow (No. 24) and
northern bobwhite (No. 25).
Three of these declining species rely on the site as a stopover during migration:
lesser yellowlegs (No. 2),
king rail (No. 4) and
short-eared owl (No. 14).
In addition to these species that are undergoing rapid declines across the United States, another 13 bird species found at Kankakee Sands are listed as threatened or endangered in Indiana. A few of these are the northern harrier, upland sandpiper, American bittern and black tern. In Indiana, Wilson’s phalarope breeds only at the restoration. In total, more than 200 species have been recorded at the restoration since 2001.