The Upper Des Plaines River Corridor is bounded by Half Day Preserve to the north, near the intersection of Route 22 and Route 21 and Ryerson Woods to the south, near the intersection of Riverwoods Road and Deerfield Road.
Located in Lake County, the Upper Des Plaines River corridor contains protected contiguous habitat totaling more than 1,500 acres. Ryerson Woods consists of 552 acres, Half Day Woods has 528 acres and Wright Woods contains 506 acres.
The Des Plaines River flows through these properties, with bottomland woods and backwaters on either side of the river. Also scattered within some of this land are fishless ephemeral ponds as well as savanna woodlands and some small grasslands.
Though this Important Bird Area belongs to the eastern tallgrass prairie region, the woodlands were part of the historical landscape. Prior to settlement by the Europeans, wildfires regularly swept eastward across Lake County, only to be stopped by the Des Plaines River. As a result, rich woodlands containing oaks and maples survived.
The Lake County Forest Preserve District does prescribed burning and removal of the non-native buckthorn to maintain these high-quality woods that provide home to amphibians, birds and rare plants.
The Des Plaines River extends farther north into Wisconsin through other preserves including Old School Forest Preserve just south of Route 176 along St. Mary's Road. The entire river corridor provides habitat for migratory songbirds as well as breeding Belted Kingfisher, Wood Duck and Prothonotary Warbler and resting and feeding places for herons and egrets.
A typical May day along the Upper DesPlaines River Corridor can yield views of thousands of migratory songbirds feeding along the river and in the myriad shrubs and trees on the property. Among the most common are Yellow-rumped, Palm, Black-and-white and Black-throated Green Warblers, with at least 50-100 of each species spotted on a single day. Chestnut-sided, Magnolia, Blue-winged and Golden-winged Warblers also use this migratory pathway each spring and fall. In fact, nearly every species of warbler noted in Illinois has been observed along this stretch of the DesPlaines River. In addition, tanagers, thrushes, flycatchers, vireos, grosbeaks and orioles migrate along the riverine corridor. These are mostly neotropical migrants, which are losing their breeding grounds as well as migratory habitat throughout their range. Indeed, birds coming from the south in spring to go to their northern breeding grounds often have little place to stop in Illinois past the southern section until they arrive in northern Illinois. Every patch of greenery and waterway is important to these birds. Here they can find food as well as shelter.
The DesPlaines River Corridor has served as an important migratory pathway for birds even before settlement, and its preservation has been important for the success of neotropical migrants.
In addition, this Important Bird Area provides breeding habitat for neotropical migrants including Wood Thrush, Red-eyed Vireo, Scarlet Tanager, Eastern Wood-Pewee, Blue Gray Gnatcatcher, Orchard Oriole, Baltimore Oriole, Rose-breasted Grosbeak and Yellow-throated Vireo. Many of these species' numbers are declining.
In total, at least 64 species of birds breed along the corridor and more than 300 migratoy and non-migratoy species have used these preserves.
This site was chosen as an IBA because it met the criteria for Migrants.
Primary invasive plant and tree species include Buckthorn, Garlic mustard and Silver maple.