Nest Site Selection and Success of Mallards and Blue-Winged Teal in 4 Cover Types in Central Wisconsin

Abstract

Duck nest density and success were determined in 4 cover types (marsh meadow, permanent grass, seeded dikes, and hayfields) located on George W. Mead Wildlife Area, in central Wisconsin. Each cover type was searched twice annually 29 April-30 June 1989-90. Mallards (Anas platyrhynchos) (n = 173) and blue-winged teal (A. discors) (n = 220) were the most common duck species nesting on the area. Nest density was highest for mallards in marsh meadows and for blue-winged teal in seeded dike cover. Mammalian predators destroyed 50% (n = 197) of the nests located; they were the most common cause of nest failure. Of the duck nests located, 79% were greater than or equal to 180 m from water. Of the successful nests located, 76% were in vegetation 16-45 cm high. Few (4) duck nests were destroyed by hay mowing. The height of residual vegetation in hayfields had no effect on blue-winged teal nest distribution; mallards avoided nesting in hayfields (n = 0.05). When data from all cover types are pooled, nest success indicates mallard and blue-winged teal populations are declining at George W. Mead Wildlife Area. Marsh meadow was the only cover type in which nest success of mallards and blue-winged teal was greater than or equal to that needed to maintain a stationary population. Thus, marsh meadow is an important component of duck nesting habitat at George w. Mead Wildlife Area.