March through June. They also graze in stubble fields and inhabit low-elevation mountain lakes and streams. Mallards are very adaptable and appear to have only a few specific requirements.
Mallards eat a variety of aquatic plants and invertebrates as well as crops.
Recruitment of mallards in the prairie pothole region of North America is low even during years of high rainfall and runoff. The creation and restoration of wetlands can increase wetland densities where low. Setting numerical goals for local populations may be futile due to regional and continental population shifts from habitat changes. Mallards are susceptible to diseases in urban settings. Bottomland oak forests serve as important feeding and wintering areas for ducks.