Stoneflies are emerging along the shores of the Middle Fork River at Kickapoo State Park (Oakwood, IL). The young of these water-associated insects are excellentl indicators of water quality, being found in great abundance in cool, clean, well oxygenated flowing waters during the spring and summer.
Stonefly nymphs are benthic dwellers, who crawl among the rocks associated with riffles areas in fast moving streams. Nymphal diet varies. Some species are herbivorous, while others are omnivorous or carnivorous.
I hope to photograph some of the terrestrial adults during the next few months, as well as photograph an adult emergence.
While climbing over logs in the wooded area on the way back to my car, I did my customary scouting for snakes in front of each log as well as the other side before I set foot down and proceeded forward. No snakes anywhere. As I approached the final path toward the car I heard a sudden, loud rattling sound about a foot to the side of the path. The snake doing the rattling was a blue-green color, about 3 ½ feet long and 3 times the diameter of my thumb. It coiled as it rattled. That was REALLY unsettling.
I held my ground. Observed that the rattling was caused by rapid vibration of the last quarter of the length of the body against the dried leaves on the forest floor. The tip of the tail was held erect as the rattling continued. I steadied my camera to snap a photo as the snake closed the gap between us, coiled, and rattled even more rapidly. Certain that it was done advancing, I steadied for a second photo. At that point the head came up even higher and the rattling intensified. I decided it was time to go home.
Once home, my trusty field guide made clear that the snake was a blue racer (Coluber constrictor foxii). A little more research showed consistent reporting that this species can become very aggressive when tormented or surprised. Some report the bite to be rather painful.
Going home, rather than continuing to photograph and further disturb this snake, was clearly the right thing to do.