Different species look for different things in a habitat. Some of the most common traits that you will see in waterfowl habitats can be the following:
A good roosting habitat is one of the first things that ducks look for. For the most part, waterfowl tend to migrate towards an area where they can feed without being disturbed. Characteristics of these areas usually have a thick emergent cover such as bulrush and cattail.
Since ducks rely on water for maintaining their plumage and keeping their eyes and nostrils clean, there will more often than not be a body of water nearby. Some ducks will experience ill health effects if without water. So, when you are scouting, always be on the lookout for open water sources.