Birds are found in every ecosystem from arctic puffins to scarlet ibis found in the rainforests. They interact with species in every ecosystem. Some of these relationships are helpful, while some are harmful.

Some relationships of birds with other species are beneficial i. e. birds and trees. Both contain the relationship of commensalism.

There are some other birds which act like a parasite ad and causes harm to other birds.

Explanation:

In commensalism, one organism gets benefit and the other is unharm. Trees provide shelter and food to the birds while birds provide no benefits to the tree. Cuckoo is a parasitic bird which lays egg in the nest of other birds. When these birds hatched, the babies of cuckoo compete with the host's own babies for food.