This is interesting, we live very full lives in cities, and become accustomed to lots of 'artificial' stimuli manmade stuff. When alone and in the 'emptiness' of the wilderness it is hard to make the switch and be in the moment of being outdoors. Books are fine and I am sure there are flat periods. I like reading something historical about the area, but I do that in camp. I take a nice plain sketch book and a field guide along in my pack and I draw and sketch. I make copious notes, check lists of birds etc. I will try to draw a 360 portrait of the view from the hide or stand. I take photos, and list animal sounds etc. This way your attention is focussed outwards and you are conscious of the surroundings and not buried in the book. The journal is as complete a record of my day as I can make it. I also hope fervently for blank spots in the record! Those will be when there are animals close by! In camp I will have other bigger books to read when we are not jawing by the fire. I once took a book of knots and a piece of cord and practised knot making, it was fun and quiet but I was looking down and not at the world around.
chrisg