Thursday, July 25, 2013

An Apparent Massasauga Rookery

We've reached the dog days of summer here in Michigan and the temperatures have soared in the past few weeks to the high 80s and low 90s. With lots of afternoon thunderstorms,the weather has not only been hot, but also extremely humid. This understandably has made finding snakes incredibly difficult during the hottest parts of the day. Since the end of May, I've been keeping an eye on a few individual snakes which have selected a prairie fen as a rookery for the summer. My first encounter with one of these snakes was back in late May on muggy, overcast afternoon.

This large female is one I've come to know fairly well over the past four to five years. She regularly spends her summer months in a small open meadow adjacent to a tamarack swamp. She gave birth to at least a dozen neonates in the summer of 2011 in that small meadow. It appears that she is once again heavily gravid this summer, but she's decided to utilize this open prairie fen instead of the small meadow which is a short distance away. She's a big snake, probably just over thirty inches in length, and heavy bodied. You can see in the video below how heavy bodied she is, and is noticeably dragging her back end due to a full load of developing neonates.

I've tried to limit my visits to once every few weeks to disturb the snakes as little as possible, and no snakes were handled in any way. I returned a few weeks later with my cousin and Chris Boguslawski and Robbie spotted the same big girl coiled in the open in the early evening. She had clearly shed her skin recently and was boldy colored. 

While we were walking out of the area, Robbie called out that he had two more snakes right next to each other. We ran over to an area where some deer had clearly been bedding at night and found these two screamers coiled side by side. Both appeared to be gravid females and were heavy bodied, though they were nowhere near the big snake we had seen just minutes before.

The snake in the top of the photo quickly bolted into thicker cover while the one in the lower half coiled defensively and sounded her rattle for a quick photo session. This particular female boasted a beautiful golden brown coloration which didn't come out real well in these photos due to the evening lighting. I saw this snake this snake a few weeks later in the early morning hours and her golden color was much more apparent. After a few photos, we parted ways for the day.

About two weeks later, I returned one early morning after a night of heavy thunderstorms to see who was hanging around the area. The sun was shining weakly through the hazy skies due to the high humidity and was perfect for snakes to be out basking before 9 AM. As I was walking through the area, I noticed a dark shape coiled in the sedges and spotted this female, the same snake that had been found side by side with the golden female a few weeks earlier. I gently pulled back some of the sedges and fired a few up close shots of this snake, she never moved a muscle.

During the first week of July my family took a trip to Michigan's Upper Peninsula; which I'll detail in a later post, and I didn't have time to return to the fen until the second week of the month. With an impending heat wave on the horizon, I arrived early one morning before nine o'clock to see if anyone was out. While walking around a section of brush piles, I noticed the golden colored female basking in a concentric coil on one of the piles. The following photo is in situ.

Gravid female rattlesnakes often select rookery sites with ample basking locations, but also consider thermoregulation as a factor. In this case, the brush piles appear to be superb thermoregulatory locations as they provide open, sun lit areas for basking and also give cover that the snakes can retreat back into when temperatures become too hot. This individual and the big female from the beginning of this post have been seen in close proximity to this area on several occasions this summer. Then, this past weekend I went out one morning with Chris to check out the area. Chris beat me to the location and mentioned he had seen two snakes up basking within few feet of each other and he thought they were two we hadn't seen before this summer. By the time I arrived, one of the snakes had gone into cover for the day, but this gorgeous gray female was found coiled near the base of a large tamarack.

The two unique spots between the saddles of this snake indicated it was one we had not seen so far this summer. She was heavily gravid just like all of the other snakes utilizing this area. We snapped a few photos and cleared out as the temperatures were rising into the high 80s already on this day. I returned early on Monday morning in hopes of seeing the second snake Chris had mentioned. Walking carefully through the area, I noticed the same snake pictured above laid out on a fallen tamarack in the dappled morning sunlight. As I was walking away from the snake, I spotted a second gravid female just a few feet away as you'll see in the video below.

I didn't disturb either snake and continued on my way out of the fen. While I was nearing the entrance of the site, I spotted this lovely snake coiled out in the open. She never rattled, but just simply raised her head to see what I was doing.

From what I can tell there are at least four different gravid females utilizing this small prairie fen as a rookery, there could even be five. Open canopy sites with optimum basking habitat like this one appear to be critical for reproductive purposes with the eastern massasauga. I'm hoping to be able to capture one of these snakes birthing with my camera, though it will be difficult to do so. The late spring we had may push that back until late August or even early September. Stay tuned...

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