Simply put, water level management at the Odessa Complex copies what happened on the Mississippi River before levees cut off most of the floodplain and navigation dams created a series of permanent pools. Prior to those two developments, the Odessa Complex was part of the Mississippi River with flowing side channels, interconnected backwaters and isolated wetland basins.
As part of the Mississippi Flyway, the Odessa Wildlife Complex contributes scarce, high quality migration habitat in a landscape dominated by agricultural production. The Mississippi Flyway is a globally significant flyway for 60% of all North American bird species and provides a major route used by shorebirds, ducks, geese, blackbirds, warblers, sparrows, and thrushes. It contains the longest migration route of any route spanning the Western Hemisphere, more than 3000 miles from the mouth of the Mackenzie River to the delta of the Mississippi River. This flyway supports an average of 36 percent of all ducks in the contiguous United States and most of the mallards in North America use the flyway. Most North American land birds that winter in the tropics also use this flyway.
Since 1995, Important Bird Areas (IBAs) have been identified and designated in Iowa based on the 37 most seriously threatened bird species in the state and the most essential habitats for those species. Supporting 24 of the 37 targeted species, the Complex is part of two officially recognized IBAs: 1) Port Louisa NWR IBA and 2) Lower Iowa River Corridor/Odessa IBA.
Most shorebirds using the Complex are long-distance migrants that require suitable wetlands where they can periodically stop to replenish their fat reserves. These staging areas must have shallow water (<20 cm or 8 in deep) and/or mud flat habitats with sparse vegetation (<25 % cover), undisturbed resting areas, and abundant invertebrate food resources to meet the high energetic demands of migration.
Bird Species known to use the Odessa Wildlife Complex:
* Total Bird Species = 240 Species
o Waterfowl = 28 Species
o Waterbirds = 34 Species
o Shorebirds = 23 Species
o Raptors = 19 Species
o Woodpeckers = 7 Species
o Songbirds (passerines) = 125 Species
(66 Species which are Neotropical Migrants)
+ Flycatchers = 10 Species
+ Thrushes & Relatives = 10 Species
+ Warblers & Vireos = 36 Species
+ Sparrows & Relatives = 24 Species
+ Blackbirds & Relatives = 6 Species
Odessa Bird Checklist
Bird species observed or known to occur.