Nerodia action

May 26th, 9am

In Lamprey Lust, I recounted the start of a long day (and week) in downtown Ithaca pursuing Northern Rough-winged Swallows nesting in drainpipes along creeks. I began the day in Cascadilla Creek, where it empties out of a gorge into the walled channel that takes it through downtown. In addition to the lamprey sightings in my previous posts, I also made some neat observations on the Northern Watersnakes (Nerodia sipedon) that are abundant along these creeks.

At Cascadilla, the morning started off with a few normal, non-noteworthy encounters with creek-dwelling Nerodia:

While heading back to climb up out of the creek bed, I practically walked right into a tangle of Nerodia on a rock shelf next to the path. I froze, knowing the skittish snakes would almost certainly bolt immediately. They didn't. They had other things on their mind and allowed me to approach within easy camera distance. I bet you can guess what is going on:


I managed to get a few video clips as they allowed me to approach so close (sorry some of them are rotated, fixing them would further reduce the quality, making it unwatchable). In this first one, the two smaller male snakes and the larger female are going at it:

In the next video, the males were being so rambunctious in their movements on the female that they actually pulled the mating ball off the rock ledge. Both males fell but the larger female was able to stay on:

Immediately after falling off the ledge, the two males were so lustly that they completely ignored my immediate presence and went crazy looking for a way back up to the ledge. The female just retreated a little farther into the wall and watched me.

Seeing a mating group of Nerodia like this was a first for me. Late May is just the right time of year I guess, for these guys, lamprey, and other critters in future posts.

I saw many more Nerodia along the creeks over the next few days. At times, while sitting quietly for long periods of time near a rough-wing nest, I could actually watch them cruise around, foraging. I watched one individual swim along the bottom of the creek, surfacing with just the tip of his head to breath and look around. He worked along the far shore, eventually wrapping himself up in a rock crevice in what looked like an ambush posture. Here he came up to breath from his crevice:


Eventually he swam away downstream, passing near enough to the ledge I was on to get some video of him swimming along the stream bottom:

The third cool observation on Nerodia was similarly while I was sitting quietly near the creek. I observed a small Nerodia swimming up close to my shore, dragging something large in his mouth. I snapped a few pictures as I approached, trying to figure out what he had, but I got too close and startled him. He dropped his prey and dashed off into deeper portions of the creek.


The prey item remained where it was, so I walked over to check it out. It was a big Tessellated Darter (Etheostoma olmstedi)! I am a big fan of darters (Percidae), for their bright coloration, bottom-dwelling habits, and especially their extreme diversity centered in the Appalachain Mountains. Relatively few species make it into NY, those that do are generally plain colored, as is the Tessellated. I was still enormously pleased to see this guy, which appeared to be a big, breeding male.


He lay there in the water where the snake dropped him, breathing heavily. There were a few pinpricks of blood from the Nerodia teeth. He didn't appear gravely injured, but he was definitely out of it. I picked him up for a better look and to confirm the ID.


After leaving the darter in the shallows, he stuck around for a while, still breathing hard. Eventually he disappeared, so he must have come around.

I have many more observations on fish, birds, and general creek life from my week in the creek, all coming soon.