Excellent watercolours, my field kit (when I can be bothered to lug it around - ie if the birding's going to be good) is - the largest sketchbook that's practical, pencils, pencil sharpener, maybe a few pencil crayons, a white wax crayon, tubes of watercolour (including ready mixed greens - not time to faff or waste blue paint), a palstic pallette, a jar, and a bottle of water. When I can, I like to take the maximum with me, but often just go out with a few pencils and maybe some crayons.
oh, and BULLDOG CLIPS! Otherwise you'll watch your sketchbook pages blow away one by one - luckily they weren't pages I'd used!