Scientists are heaping praise on a 96 year-old man who is devoting much of his time to saving bluebirds, whose population is dwindling rapidly.

Al Larson, also known as “The Bluebird Man,” first became passionate about bluebirds when he read a piece on the National Geographic about how simply building bird houses could help to curb their declining populations. Al soon noticed a bluebird going in and out of a dead tree in his yard, and this caused him to start setting up little boxes that could be used as nests by bluebirds.

“I got carried away,” Al said. “I settled on a simple design that [was] easy to build and easy to monitor. I kept adding more boxes on these trails, and these birds responded.”

What was originally a hobby to give him something to do after retirement soon effectively became a full-time job, as Al has since built 350 birdhouses placed across southwest Idaho in the past four decades. His efforts have banded and documented over 30,000 bluebirds, and during each summer nesting season, Al travels over 5,000 miles to check on all of his boxes.

Since bluebirds live in dead or dying trees, the invention of the electric chainsaw in the early 1900s wreaked havoc on their population, as it was easier for people to get rid of dead trees. The implementation of pesticides made things even worse for the bluebird population, but Al’s efforts have shown that there is a away that we can safe them.

Though he is about to turn 97, Al is still as passionate about what he is doing as ever. His inspiring story has even been made into an Emmy award-nominated documentary “Bluebird Man.”

“Al is a living example of how much one person can achieve when they set their mind on a task. But he’s also an example of the benefits that a project like this can have for people,” said filmmaker Matthew Podolsky. “[Bluebirds] have given meaning to Al’s life, and they are truly the secret to his longevity.”

Check out the trailer for this below!