It is always good to know the name of that thing you are drawing. So, if you are an artist and you are out in the field, I highly suggest taking the extra step of cataloging your observations. iNaturalist is an online community for naturalists and a amazing resource/research tool for artists. Without a doubt it is the next best thing to dragging a biologist along with you on your next sketchbook outing. You can upload pictures of the little critters you find and get help identifying them. They have an iPhone App which is very handy.