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THE DECLINE OF GRASSLAND BIRDS IN THE CHICAGO REGION VIGNETTE
Daniel Suarez, Audubon Chicago Region
June 27, 2015
Photo by Valerie Spale
Grasslands were the most dominant landscape feature in North America in historic and pre-settlement times. The most dominant plants of the historic prairie were grasses and sedges.
Grasslands were also the most dominant landscape feature of other continents around the world. These grasslands include the Steppes of Central Asia, the Plains of Africa and the Pampas of South America.
Grasslands are fire dependent ecosystems. They developed over millennia claiming many thousands and thousands of acres across the world. Most of the biomass of grasslands are held deep in the soil beneath the surface of the ground. 35% of all carbon on earth is held in grasslands. Grasslands are one of the most effective carbon sinks in the world and help reduce pollution - an economic benefit to global economies.
Grassland vegetation grows to incredible heights - taller than a man on horseback. Stories tell of early settlers getting lost in the prairie because they could not see the horizon.
Types of Prairies
Wet prairie - wet mesic
Dry prairie - dry mesic
Dry/sandy prairie - fast draining
Chicago was covered by a sheet of ice a mile thick during the last glacial age. When the ice began to retreat, more than 12,000 years ago, the ground was scoured into vast flatlands. Meltwaters created kettles, moraines and kames, formed eskers from leftover debris and created rivers and valleys.
Prairies depend on fire and smoke for seeds to germinate. Prairie fires started by lightning strikes or Native Americans kept prairie ecosystems and other natural areas healthy in the centuries prior to settlement. Prairies can survive cycles of drought or onslaughts of rainy weather.
Early settlers believed the prairie was worthless and infertile because there were no trees on the land. It was not too long before the value of prairie soil was discovered - the richest soil in the world. Following the invention of the John Deere steel moldboard plow, extensive acres of prairie were destroyed as the land was converted to agriculture. Land development for immigrant communities and cities also contributed to the loss of the prairie, woodlands and open space. Today, only l/1000th of 1% of high quality prairie remains. Prior to settlement, 75% of Illinois was prairie, covering the vast majority of the central plains of Illinois and sections of northeastern Illinois.
Buckthorn and other invasive plants, introduced to Illinois by immigrants from Europe or Asia, quickly took over what native landscapes still remained, followed by a cessation in the fire regime.
Drain tiles were installed to make more land available for farming. Wetlands were destroyed as well. So many drain tiles were installed that they could wrap around the world six times.
Agriculture, development, alteration in hydrology, fragmentation, edge effects, roads, and fire suppression led to the near extinction of the Illinois prairie and its plants, birds and animals. The quality, plant diversity, habitat for wildlife and birds tottered on the brink of extinctions until conservationists began to realize that the prairies of Illinois needed to be saved.
One of the first things conservationists did when natural areas restoration began, was to remove drain tiles and try to stabilize the hydrology of remaining natural areas.
Following drain tile removal, prescribed burns were introduced and invasive species were removed.
Grassland birds and shrubland birds are the fastest declining suite of birds in North America with many populations dropping by over 40% in the last 40 years.
These species are in peril because of habitat loss, agriculture, urban sprawl and invasive species. They include the Bobolink, Meadowlark, Sedge wren and Henslow sparrow. Since l968, 24 species of birds have declined by 40%. Some are down over 90%.
Male Bobolink - Photo by Greg Lasley
The Bobolink overwinters in the grasslands of Argentina and returns to the Chicago area in spring. The last Bobolink recorded at Wolf Road Prairie was in 2012. Bobolinks prefer mesic prairie dominated by big blue stem and other taller grasses. Bobolinks feed on insects, beetles, wasps, spiders, ants and prairie seeds.
The Henslow sparrow winters in a range of southern states and northern Florida. They migrate by night. They are tolerant of taller vegetation and perch on goldenrods and stalks of rattlesnake master. They do not associate in flocks and like thick thatch for habitat and nesting.
The winter range of the Grasshopper sparrow is Mexico and Central America. They migrate at night. They prefer drier soil, shorter vegetation and no brush. They search for food in thatch and dig for insects. They forage by hopping on the ground. They change their nesting areas from year to year.
The Eastern meadowlark leaves late and arrives early during migration season. Some have been known to overwinter in Illinois. They tolerate a wide range of habitats and can mate up to three times a year. The most recent sighting of a Eastern Meadowlark at Wolf Road Prairie was in 2012.
The Sedge wren is tolerant of taller vegetation. They are nomadic and can occupy multiple habitat sites. The Sedge wren prefers wetter areas with sedges and lives in small colonies. The Sedge wren is an aggressive bird and is known to puncture the eggs of other birds to prevent encroachment upon its territory. It nests on the ground and builds dummy nests to distract predators. The Sedge wren feeds on an array of insects and forages in low grasses and sedges. It will take short flights to catch insects in the air.
50% of endangered bird species migrate north to Canada.
By 2080, climate change will result in increasing temperatures and reduce present acreage of suitable habitat for grassland birds. As grassland birds are pushed to migrate further north, they will encounter more forests than grasslands. They will not find the food sources they require in the forests or appropriate nesting sites. Species already in decline will be in further peril unless efforts are made now to reverse this loss. A solution is to increase large scale preserves for grassland birds in the Chicago Wilderness region and provide nesting opportunities to increase population numbers and breeding pairs.
Audubon Chicago Region
Photo by Saskia Heijltjes
Audubon Chicago Region is dedicated to the long-term viability of our region's grasslands, through recruiting and training restoration volunteers and monitors, engaging landowners in grassland restoration best practices and using scientific analysis to identify key strongholds for these species in the face of climate change.
Audubon Chicago Region projects and goals:
1. Holds workshops and recruits volunteers to restore more grassland areas
2. Project restoration sites include: Bartel Garasslands, Spring Creek, Orland Grasslands
3. Works to further understanding of grassland conservation success, grassland bird migratory routes and destinations and life cycles of grassland birds
4. Designs and manages grassland restorations, monitors progress, shares goals and methods with conservation partners
5. Records grassland bird population numbers and sizes of restored grasslands
6. Creates a data base of bird numbers, establishes ecosystem service value of restored grasslands and recommends spatial areas for conservation work with public landowners in the Chicago Wilderness area
Grassland Bird Population Goals for 2025
500 breeding pairs of Henslow sparrow in the Chicago Wilderness (CW) region\
2.500 breeding pairs of Grasshopper sparrow in the CW region
50 breeding pairs of Upland sandpiper in the CW region
1,000 breeding pairs of the Sedge wren
Goals for Grassland Habitat Reserves
Orland Grassland restoration project in Orland Park, Il.
Photo by Cassi Saari
9,000 acres of dry grasslands
9,000 acres of wet/wet mesic grasslands
9,000 acres of mesic grasslands
Midewin Preserve - 4,000 acres - grassland complex
4.2 billion dollars in value as flood control, water purification, groundwater recharge and carbon storage. Bobolink habitat also provides flood control and retention
Grassland Birds at Wolf Road Prairie
Wolf Road Prairie provides 40 acres of suitable grassland bird habitat
Wolf Road Prairie provides insect biodiversity
Wolf Road Prairie provides intact soil biota
Wolf Road Prairie provides proximity to additional open space and habitat at nearby golf courses, cemeteries, Hickory Lane bufferland and forest preserves. These areas enlarge preserve size and provide a variety of nearby ecosystem types, food sources and nesting sites.
To learn more about Grassland birds and their habitats and what you can do to help right here in the Chicago Region and for more information about Audubon Chicago Region, go to: www.chicagoaudubon.org
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