Each species of warbler eats insects in its own small part of the forest, hardly ever crossing invisible borders to enter any other warbler's area. So several different species can all live in the same small stand of trees. Although warblers are shaped pretty much the same, most species are specially adapted for taking insects in one particular area, called their niche. Groups of birds that can live together in the same area like this are called communities. Warblers form an important part of breeding bird communities in North American forests.
Some warblers are specialists.
These birds virtually always take their insects from one particular part of a tree. Blackburnian Warblers glean for insects in the canopy of trees, especially on small twigs and leaves. Magnolia Warblers feed at low and medium levels, especially in the understory, and catch many flying insects. Chestnut-sided Warblers take insects from the undersides of leaves, especially in low and medium levels. Ovenbirds feed on the forest floor, probing around and under fallen leaves for food items.