University of Illinois Extension
The Illinois Steward
Aerial survey—Aerial surveys use aircraft to systematically assess waterfowl numbers and habitat conditions.
CFWs—CFWs is an acronym for “confusing fall warblers.” The term is often used by birders to describe the mix of migrating fall warblers. Immature warblers of many species that have yet to attain their species-specific adult plumage are very similar in appearance and very difficult to identify during the fall migration.
Dabbling duck—Dabbling ducks feed on or near the water’s surface, often with their tails above the surface and their heads under water. They feed on the usual fare, including all sorts of plant materials and invertebrates, such as coontail, algae, millet, marsh smartweed, corn, and midge larvae. Dabbling ducks are members of the genus Anas and include the mallard, gadwall, and blue-winged teal.
Diving duck—Diving ducks dive to forage for food or for protection. For example, the lesser scaup feeds on snails and mussels in this manner. However, these ducks also eat common fare, such as coontail, pondweed, and invertebrates. Diving ducks are members of the genus Aythya. In addition to the lesser scaup, other species of diving ducks include the canvasback, redhead, and greater scaup.
Emergent vegetation—Emergent vegetation is vegetation that grows in standing water within a wetland and extends above the water. Examples include cattails, arrowhead, and pickerelweed.
Hemi-marsh—A hemi-marsh is a wetland that has a significant amount of emergent vegetation interspersed throughout the open-water portion. Typically, about one-half of the area in a hemi-marsh is emergent vegetation, and the rest is open water.
Obligate wetland species—An obligate wetland species is one that cannot complete its life cycle without wetlands—for example, a species that only nests in wetland vegetation, as do many waterfowl.