Mallards are dabblers.

Multiple species can inhabit a certain ecosystem because they each have their own ecological niches. An ecological niche is determined by the species' living habits.

Let's take mallards as an example. Mallards are a duck species that often inhabit lakes and other freshwater ecosystems. They are dabbling waterfowl, which means that they are unable to dive in search for food, instead only tipping their bodies halfway under the water. Because of this, they search for food mostly in shallow shore areas. Mallards eat mostly plants and small animals found in the shallow shore water. Thus, the ecological niche of mallards can be outlined as shallow lakeshores. 

Tufted ducks often inhabit the same lakes and areas as mallards. They too eat plants and animals they find under water. Why haven't the tufted ducks driven the mallards away from these ecosystems completely?

The reason is that tufted ducks are diving birds. As a result, they can search for food in deeper waters than mallards can. Thus, the ecological niche of the tufted duck can be outlined as the areas of the lake that are deeper than the shallow shore.

Constant interspecific competition is very taxing on organisms. This is why, when observing the natural world, we can notice different ecological niches instead of a constant struggle for resources. Ecological niches provide each species with sufficient resources to live, survive, and reproduce.


Tufted ducks are divers. The picture shows a female diving under water in search of food.