The results of a comparative study of a trophic spectre of three species of shorebirds(Tringaflavipes. CalidrisfuscicollisandCharadrius collaris), are given in this contribution. They show the mechanisms of isolation despite sharing the same source of food. Considering the diversity of food, the mechanisms of isolation can be shown in the trophic as well as in special dimension of the ecological niche. Specialization on certain types of food and different types of habitat use are the prevalent strategies to avoid competitive exclusion.