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Grassland

areas vegetated with various mixtures of grasses, forbs, and short woody species (such areas were normally grazed).

Grassland-Idle

same as Grassland but situated on land owned by the Fish and Wildlife Service and normally ungrazed.

Hayland

areas that have been plowed and seeded to mixtures of grasses or legumes for forage production and that are hayed annually (Native grass or wetland areas that are occasionally hayed were included under grassland or wetland.).

Planted cover

areas that are planted to mixtures of grasses and legumes for producing wildlife cover or for stabilizing soil under land retirement programs, except Conservation Reserve Program lands.

CRP

agricultural areas enrolled in the Conservation Reserve Program during the current nesting season.

Cropland

areas that are planted to grain or row crops, or that are plowed and left fallow.

Woodland*

areas dominated (areal coverage greater than 30%) by trees or tall shrubs (6.0 m or greater in height).

Shrubland*

areas dominated by short shrubs (0.5-6.0 m tall).

Oddarea*

small patches of cover (less than 2 ha in size) surrounded by large areas of a cover class characterized by shorter vegetation (also included features such as rock piles, hay bales, shelterbelts, and farmsteads, regardless of size).

Right-of-way

areas between road surface or railroad bed and adjacent fence line or cropland border.

Barren

areas where there is no probability of a duck nesting, such as road surfaces, mud flats, and open water.

Wetland

all areas defined as wetland by Cowardin et al. (1979) that contained emergent nesting cover except scrub-shrub and forested wetland. Semipermanently flooded emergent wetland is composed of a mixture of emergent cover, in which a bird could nest, and open water or submergent vegetaion. We converted half of the area in this class to barren and half to emergent nesting cover. We had no data for nesting in scrub-shrub and forested wetland. For analysis of nesting, scrub-shrub and forested wetlands are physiognomically more like areas classed as "other habitats" than wetlands so we included them in that class.

Island

naturally occuring and created islands.

* for purposes of summarizing nesting results, woodland, shrubland and odd area habitat classes are combined into a class called Other.

References

Cowardin, L. M., V. Carter, F. C. Golet, and E. T. LaRoe.  1979.  Classification of
     wetlands and deepwater habitats of the United States.  U. S. Fish Wildl. Serv.,
     FWS/OBS-79/31.  103 pp.