So, the fauna and flora were drawn on vellum, which is like a heavier, slick tracing paper. You can draw on the front (I used color pencils) which has a tooth to it, and paint the slick surface on the back (gouache) so that it's no longer semi-transparent. The objects in the circles have this "back painting" and thus really pop out because they are 100% opaque. The whole piece is placed on a piece of sage green paper, which gives the rest of the semi-transparent scene a green undertone.
I've got to mention how the labels were done "back in the day." Once complete, I scanned the art to digitize the file, and placed it in Quark Xpress. Using the image as a guide, I typed in labeling/arrows on a layer on top of the image; the quality of which was a blurry, pixelated version, as Quark and computers weren't robust enough to generate a clear image without crashing the program. Then that label file went to a local printer to print on clear acetate. I had to re-do it since one of the arrows didn't line up the first time, and each printing cost $40.00! It's safe to say I skipped many a meal that week.
Mean time, can anyone spot the type-o? It's the black-capped chickadee, not the "chicakdee." An old high school friend spotted it YEARS after I finished grad school!