Glad you got your decoy back but no offense I think he had every right to pick it up if your not hunting over your decoys and they are not tagged with your name and at least phone number its trash and should be picked up. Him lying about it was not the right thing to do that is for sure but being an avid duck/goose hunter if I see a duck decoy floating around this time of the year im going to assume someone lost it over the season and or had it fallen off someones boat during the season. I expect the same thing from anyone thats why I use a marker bouy with my name on it and not a decoy. Sorry I don't agree with your opinion on this one. Since well if its floating with no tag its really not yours, its trash.
By the way If the value of his tires is over 500.00 you would have commited a felony. I dont see a decoy being a justifiable trade for a permanent mark that will follow you for the rest of your life and if you do......Well I think I will just leave it there.