You have some good shots there. Check your camera I am sure you have some sort of sepia tone or B&W setting on your camera. Play around with your framing don't always put your focal point dead center. Use the rules of thirds and put things off to the sides. Also with nature photography try and keep man made objets out of the picture. Just as a fun exercise go to the zoo and try to get shots of the animals without the man made stuff and see what you can come up with. Keep it up!!