Sketchbook and Drawing Materials
A spiral, hardbound sketchbook. It give one more room to swing and gives room for one to put more "poses" on the page. The regular cloth-bound sketchbook can't bend backwards without breaking the spine. Hardbound is good to stabilize the arm or to lean it on the railing, it's basically a good flat drawing surface. Here are some of the sketchbook I recommend, and personally use, out on the field.
The second one is Aquabees, this sketchbook hold wet medium well and regular drawing utensils. It can be bought in any art store like Blick and Utrecht.
Lastly I also use Komtrak, this one you would have to order on your own since it's not sold in regular stores.
As for drawing utensils, I suggest trying out several kinds of pencils, brush pens, pens, and markers, also something that travels easily. Be aware that different brands of pencils (colored or not) have different hardness and waxyness. Here are some supplies that I use.
Water brushes and Pentel Brush Pens:
Close up of brush pens (below)
Pencils (with the same erasers as above):
Close up of pencils (below)
Different pencils are made differently and feel different when using it, not to mention that the value of them can vary as well.
Close up of pens (below)
These are white gels pens (below)
If you have never used different materials before, experiment. With such a wide range of subject matter to choose from, you never know when a new drawing process will fit the job perfectly.
What do you carry all this gear in?
More than often, drawing animals is an all day affair, moving from one site to another. This is one pencil case I use to put my supplies in, you're welcomed to use whatever you feel most comfortable.
I also choose a medium sized hip-pack instead of a small backpack to keep the weight off my shoulders. A fanny pack with a couple of good sized zipper pouches allows me to store lunch or some energy food.