1. Birds like hawk or kingfisher occupy the higher trophic levels.
2. They feed on smaller prey like small birds, frogs, fishes, snakes, etc. These smaller animals feed on insects which already may have accumulated some amount of DDT due to their feeding on plants having DDT content.
3. Since non-biodegradable DDT remains in tissues of organisms, larger birds will receive the maximum dose of DDT.
4. As the phenomenon of biomagnification occurs in case of nonbiodegradable DDT, the amount of DDT will go on rising from plants → insects → smaller animals → then to larger birds. Birds of prey will thus have maximum DDT in their tissues.