I think I did a post not too long ago about these people. What I think this story best highlights is that it really takes minimal effort to achieve important results, people just actually need to do it.
He put up some owl boxes, and made nice areas for the owl's food to live too. It was land that wasn't useful for anything for people, and now it is bringing back the owls.
The owls need a good supply of rodents, such as wood mice, field mice, and shrews.
He has turned parts of the land that are not being used for arable farming into wild bird cover with rough grass areas to allow these types of animals to thrive.
Getting neighbors to stop using poison will be the big challenge. Poisoned animals are easy to catch as they succumb to the effects, and are taken back to be shared with the nest. They're also eaten by pets and other wild animals, killing them all very painfully. Poisoning is terrible and should be stopped.