Pigeons definitely recognize vehicles after a while, and guns if they live long enough. Your best camo is what everyone else in the yard is wearing, that is what they are use to seeing. Crows are even worse, they recognize you. I use to always wear this big hat and a white shirt on a farm and I had shot a few Crows one year and then I had stopped wearing the shirt and shooting crows. Fast forward to next summer, it's hot out, I put on the hat and the shirt and has soon as I walked out the door the crows 200 yards away started screaming! They have awesome memories. I actually stopped shooting them after that, unless they were in the corn. They don't touch the corn much anymore. I actually feed them chipmunks now. That is a another story, clever birds.