After walking all day you want to rest for a while and where to do that better then in that house your passing. Let’s ask first. Talk to the man standing in front of his house. Ask him what he’s doing there and you’ll learn that he lost his key and that a bird took it. That focusses your attention on the tree. There’s a bag hanging in it. Look at it and you’ll see it’s full of birdseeds.
Take the PLANK standing against the house. Bob doesn’t mind. Try using it on the bag to get it out. It doesn’t work. Walk further to the right and there’s the bird. On the treestump is a BUCKET. Walk back to the left and in your inventory use the bucket on the plank and use the combination on the BAG of seeds. That’ll work!
Walk to the right again and lure the bird with the seeds by using the bag on the bird or the stump (where it ends up anyway). Once the bird is eating from the seeds, take the BIRD. Walk back to the left and give the bird to Bob. He knows how to get his key back…
Game source: A copy of the game was found here on the internet.