Threats to the apple tree include certain harmful fauna, such as worms that eat the fruit, or mice that eat away at the roots. These effects are counteracted by setting up nests for the birds that will devour mice and worms, as well as other species that threaten the apple tree.

Coal tit, blackcap, blackbird, finch, owl, thrush, robin… are some of the birds that help establish biological control of the apple tree, and keep its main threats at bay without the need for human intervention.