Biotic factors are living things, such as plants and animals, that affect or influence their ecosystems and the lives of other living things in the environment. The biotic factors in an organism's environment include both the prey that the organism consumes and the predators that consume the organism.
For example, when considering the biotic factors of a robin's environment, one must consider the berries, seeds, worms and insects that the robin eats as biotic factors. In addition, the owls, falcons and cats that eat robins are also biotic factors. The animals that consume young robins and robins' eggs, such as raccoons and crows, are also biotic factors.