Mottled duck habitat use and density density indices in agricultural lands

We established indices of mottled duck (Anas fulvigula) diurnal habitat use and densities in the agricultural areas of southwestern Louisiana during 9 aerial surveys, May 1984-April 1985. We identified 15 habitats on the area. Habitat composition of transects varied among months. We observed fewest ducks and smallest flocks (ducks observed/observation) in June, highest counts of ducks in August, and largest flocks in July. Flock size was greatest in July on ponds. Habitats used most frequently were fresh marsh, rice, and flooded harvested fields. Density indices stratified by habitats differed (P < 0.05) among surveys and varied from 0.23 [+ or -] 0.04 (SE)/[km.sup.2] during June to 2.65 [+ or -] 1.23/[km.sup.2] during August. The most precise density indices of mottled ducks were made during March, April, and June surveys.