Photinus Carolinus, the "synchronous" firefly, found in the Great Smoky Mountains outside of Gatlinburg, TN, is quite a sight to behold. I recommend everyone see it at least once.
To maximize your enjoyment of this natural, precious, and rare wonder of the world, I have the following list of suggestions...
- See them around June 3rd or 4th, if at all possible. Though other species peak at different times, Photinus Carolinus seems to be at its most populus around these days.
- Go on a night when the moon will be waning or new. A waxing moon is too bright and will be directly overhead at exactly the wrong time of night. Given this, 2012 will be a bad year. 2013 should be excellent, though.
- Bring your own folding chair. You will be sitting for a long time. Not only in line for the bus to Elkmont, but also in the forest, waiting for the fireflies to start flashing.
- Leave your children under 12 at home or in Gatlinburg. They will be an annoyance to you and everyone else around you.
- Wear jeans and long sleeves. Aside from it getting a little chilly after dark, the woods have lots of chiggers. Using Deet or other insect repellant is strongly recommended. Take it from someone who learned this the hard way.
- Enjoy the other species of firefly that will be flashing on the same night. One with an amber light (perhaps Pyractomena, but maybe Photinus Obscurelis) during twilight, and another (Phausis reticulata) with a pale blue light that flits around in a most charming fashion after dark (I swear to you, you will be charmed), nicknamed "the blue ghost".
- Stay on the path. See #5 above. If you're there early enough in the month and the moon is waning, the fireflies will be ALL AROUND YOU once it's dark enough (which isn't going to be until after 10 pm, so, again, see #4).
- Pick a spot where you can see a decent-sized area, away from obscuring boulders and/or structures. When the fireflies are in full effect, the light pattern moves across the forest floor in waves. Keep in mind that the males are putting on a show for the females in the leaf litter. That should give you an idea about what spots are likely to be the best.
- Sit in quiet repose, contemplating life, mortality... its beauty and brutality.
- Try to take movies or pictures of the fireflies (unless you seriously make your living with a camera, preferably as a nature photographer). Not only is this not going to work, it's going to annoy everyone around you and furthermore make you look like the moron that you are demonstrating yourself to be.
- Stray off the path. See #s 5 and 7 in the prior section above.
- Bring a bright flashlight. Even the dim flashlights are incredibly annoying and essentially unnecessary if you stay on the path. You will find that, A) There are many morons around you with their own flashlights and astoundingly little awareness of just how annoying they are being. They will provide more than enough illumination; and B) Even without the morons and their flashlights you will find that your eyes will adjust quite well and you'll be able to find your way back to the trolley (or your car if you've gone earlier than the start of the trolley service).
- Bring young children. Photinus Carolinus fireflies don't start flashing until it's well and fully dark. In June in TN this means 9:45. That's when the fireflies GET STARTED. YOU WILL WANT TO STAY UNTIL 10:30 or later, at which point there will be a long line for the buses back to your car. A line that will be filled with dumb, inconsiderate, fucking stupid people who brought their now incredibly cranky young children. I guarantee that you will not be BOTH seeing the fireflies AND getting back to your car before 11 pm. Not going to happen. Do your young children regularly stay up this late??? Do you want to sit with them in the hot, humid, Tennessee forest, literally for HOURS AND HOURS with virtually nothing to do but be patient and wait, meanwhile annoying the shit out of everyone around you (if not also you), only to then be forced to completely miss what you came to see because they can't manage to make it until 11 pm without throwing fits?