John, I spend a lot of time paddling marshes and really enjoy it, I think you will find kayaking marshes to be a great immersive experience. I doubt camo pattern will help much but a wood kayak is better than a composite one, white and blue are the colors birds see vividly so avoiding those colors is good. I think what works against you in a kayak is that you are moving and you have a wide wingspan. If you like to stop and observe the birds place your paddle lengthwise to the hull instead of cross wise. When approaching birds I think their are 2 good approaches. Just ignore them and move in slowly acting occupied with something else (pretend you are a fisherman) or just go plowing through and don't change your paddling pace or direction. Birds are sensitive to stalking. Also be sure to be sensitive to the nesting period and aware of the restrictions many of these places have. Let us know how it goes.