A- Shout "LET'S GO CHAMP!!"
B- Call the Mythological Creature Control hotline and let them take care of it
C- Throw some meat at the big, hairy sasquatch to see how he/she reacts?
D- Find the worst kind of camera you can find, and take the worst picture of all-time to post online as "evidence". 
I'd call my sister-in-law's husband and tell him to come get her.
Maybe you haven't been listening to Mott The Hoople lately. I have. Lol:)
It was the word "backyard" that made me come up with my answer. Lol:)
Keep my distance and leave some vegetarian food and fruit for him every day until he becomes less shy.
Build a small cabin for him with an open door, plenty of windows, and a king-size mattress.
Continue normal gardening activities and hope that he decides to hang around and become friends with us.
