I was very excited to continue from the summer to fall fieldwork with the OTCC this year. It has been so interesting to see the behavioural changes of the study turtles and the changes within the field site habitats. As a bonus, the cooler weather meant fewer biting insects! One big change at the field sites that I noticed, was increased water levels with all the rainy fall days. This meant the study turtles had easier access to many different parts of their wetlands that were previously dried up. It was quite a fun adventure finding the turtles since many of them moved with this increase in water. This movement was the beginning of their search for a suitable hibernation site to overwinter in. We found that many of the study turtles returned to similar areas where they have been found to hibernate in the past. This year, the study turtle T016 decided to move into the thicket pictured below:
Pictured is the thicket that study turtle T016 moved into.
This thicket was likely dried up throughout the late summer to early fall but is now an excellent habitat for this turtle to hibernate in. Thickets are great hibernation spots for turtles, but it can be tricky to track them in – we were lucky on this particular day, T016 decided to pop up and say hello!
Pictured is study turtle T016 saying hello.
Where, when, and how do turtles hibernate?
Along with the shrubby thicket where we found T016, turtles may also overwinter in leaf litter-lined vernal pools or the muddy bottoms of lakes and ponds. The leaf litter and muddy bottoms of these habitats provide extra warmth throughout the colder months. Another important factor in a turtle hibernation site is the amount of oxygen in the water. In the winter, there tends to be more oxygen available in deeper water. A high oxygen level is very crucial to the turtle’s survival since they will remain inactive until they emerge in the spring. Some turtles will congregate together to the same spots every year. Pictured below, are two study turtles, T300 and T087, and one wild Blanding’s Turtle that we found all in the same spot. Perhaps they will be hibernating together!
Pictured is study turtles T300, T087 and BLTU-101 all found in the same spot!
Although fall is the time where turtles will start to slow down and get ready to hibernate, we found with warmer weather this particular fall, they remained quite active and would come out to bask on the hot, sunny days. In the photo below, T344 can be seen basking discreetly in the shrubs. On the cooler days, we would usually track/find the turtles staying warm underneath shrubs, grass hummocks, or buried in mud underwater.
Pictured is study turtle T344 found basking in a shrub.
Once turtles enter hibernation, their heart rate and metabolism slow down and they no longer require to eat. Since they will be remaining underwater over winter, they have special adaptations that allow them to breathe. To do this, the oxygen in the water passes over an opening on the underside of their tail called the cloaca. The cloaca has many blood vessels that will intake oxygen and output carbon dioxide to keep the turtle alive.
Now that the field season is over, we are wishing the study turtles a safe winter and we can’t wait to see them again in the spring!