OMG I FOUND A PIGEON OUTSIDE MY GARDEN AND...?

Take it in, I have 3 pigeons who have been hurt or stranded in my house right now. No joke. Just pick it up with a towel, or gloves, and put it in a box. See how it acts around you, if it doest mind you very much, it could very well be tame. If thats the case, you might like to do what I have: let them out, and regularly leave food where it would see it. Soon, you will have an outside pet.