Imagine you have a nice house that you no longer need. Sometimes, other friends might come and live there after you go. When woodpeckers stop living in their nests, other birds can move in and make it their home. This way, the nests can be used again and again by different birds over many years!
You can say it like this: 'After woodpeckers finish using their nests, other birds can come and live there for a long time.' Or, 'When woodpeckers leave, their nests become a cozy home for other birds for many years.'