Birds eat the sweet berries and thus spread the plant seeds.

Plants produce berries and fruit to spread their seeds. The sweet taste tempts animals, especially birds, to eat and thereby spread the seeds.

When a bird eats a berry, it digests the fruit pulp, but it cannot digest the seeds. These are regurgitated or passed through the bird’s digestive system. In either case, the seeds likely end up in different environments, increasing the chance of some of them taking hold. At the same time, the seeds will not compete with the original plant for water, light and nutrients, as they would if they germinated nearby. Consequently, sweet fruit is an advantage for both the plant and the bird.