What is the relationship between black woodpeckers and honey bees? The answer lies in the holes that woodpeckers make into trees, which can later become natural hives for bees.
A study carried out in Germany and published in Apidologie examined which tree cavities were preferred by honey bee swarms. The results showed that bees favored larger cavities with smaller entrances located near the bottom of the hollow, typically 8 -10 meters above the ground. No specific preference was found regarding the direction of the entrance. These features likely provide better protection and more suitable nesting conditions.
Researchers concluded that older, naturally enlarged woodpecker cavities can serve as ideal habitats for wild honey bees. The findings may also offer useful ideas for the design of artificial hives.

Go to the scientific paper here.