Had a grey bark at a set I was on in florida a couple of years ago, and I don't believe it had anything to do with breeding season. I was set up on a corner of a new clearcut, with palmettos at my back and two fallen trees in front of me. I set my fanny pack on the tree with my Contender on top of that to have it ready. After several minutes of calling, a grey came from upwind at the roots of the trees, and ran down the trees to my gun. He barked once and went to the other end of the tree where he barked again, then back to the gun, barked, then to the roots and barked. This went on about three times until he came back to my gun and decided he would mark it for his territory so I scarred him off. Cleaning fox pee off a Contender and scope is not an easy task. On the upside, I had fresh cover scent the rest of the day. All this went on about two feet in front of my face, but I just don't think it had to do with looking for a mate, but I could be wrong.