Always More to Learn About Turtles

Lesley Rudy is our guest blogger today. In this post, Lesley will outline some of the things she has learned about turtles in Kingston, while she was completing her Master’s at Queens University.

In 2018 I started a research project on turtle nesting and the emergence of hatchlings from the nest. This research developed into a Master’s thesis paper that was completed with lots of support from Friends of Kingston Inner Harbour (FKIH) and their volunteers.

The Friends of Kingston Inner Harbour (FKIH) have been working to protect turtles since about 2015.  This has included covering turtle nests to protect them from predation, installing signage, doing public outreach and education, collecting observations to submit to the Ontario Reptile and Amphibian Atlas, a radio telemetry project to see where turtles go and more.

Four species of turtles are known to nest in the inner harbour: Northern Map, Painted, Snapping and Common Musk. My research focused on Northern Map turtles as they are the most abundant at this location and their nesting is less studied than some of the other species.

Due to the possibility of hatchlings staying in the nest over the winter and emerging the year after they were laid, it takes a full year to study a turtle nest and get all of the information possible. My thesis included data from the 2018/2019 and 2019/2020 seasons. Data collection also occurred during the 2020/2021 season and will be included in the analysis for the upcoming published research paper.

It’s illegal to alter turtle nests and confine turtles!

Ontario turtles are species at risk and thus anyone handling turtles, altering turtle nests, or confining turtles must have the appropriate permits (it is illegal otherwise). As such, each year I applied for the proper permits so that I could complete the turtle research.

About the research

To study the emergence of hatchlings, my colleagues and I surveyed the study area every morning and most evenings during the nesting season to look for nesting female turtles. When one was located, we followed her while she chose a spot and waited for her to finish nesting. This can take hours! We then covered the nest with a nest protector box to keep the nest safe from predators.

Data on date, location, species and other things would be collected. I would then carefully uncover the nest to the top egg, put a temperature sensor in and carefully replace the and the nest protector box. Unlike the nest protectors used in conservation (such as those sold by Turtles Kingston), these covers did not have escape hatches for hatchlings as we needed to be able to collect data on hatching success. To ensure turtle hatchling safety, I would survey the nest boxes two or three times a day for any emerged hatchlings, then record and release any hatchlings found. This would allow me to know when precisely the hatchlings emerged from the nest and to collect data that could be compare to other factors like the laying date, nest temperature and other environmental data.

So, what has this research found so far?

1.     Nesting of Northern Map and Painted turtles at this location can start as early as May 31 and continue as late as July 19.  Painted turtles seem to start nesting a few days or a week earlier than Maps. (three seasons data)

2.     Hatchling Map turtles were observed emerging from the nest in the fall anywhere from August 27 to October 27 OR in the spring anywhere from March 10 to June 15. (three seasons data)

3.     78% of nests laid produced at least one live hatchling (three seasons data)

4.     Of nests that were successful, 78% of Map turtles stayed in the nest for the winter (three seasons data)

5.     Some clutches of hatchlings will all emerge within a few hours of each other, but sometimes they emerge over several days or even weeks. 58% of clutches all emerged within 24 hours, 28% emerged more than 24 hours later, but within a week, and 16% took more than a week to emerge (two seasons data)

6.     Time since laying does not relate to emergence time (nests that were laid earliest did not necessarily emerge earliest; three seasons data)

7.     Accumulated heat does not relate to emergence time (nests that were warmer did not necessarily emerge earlier; three seasons data)

8.     Overwinter survival only related to temp insofar as nests going below about -8C do not survive (three seasons data)

9.     There was a higher likelihood of hatchlings being present after rain. However, this does not mean that they only emerged after rain as some emerged when it was bone dry! (two seasons data)

10.  Lower air-nest temp difference also showed a small increase in likelihood of hatchlings (two seasons data)

11.  Compared to the other two studies on Map Turtle emergence done in Indiana and Pennsylvania, turtles here had a lower overwinter survival and higher incidence of fall emergence (in Pennsylvania and Indiana fall emergence was rare; two seasons data)

What else did we study?

I also started a mark-recapture project to try and estimate the population size of the turtles in this area.  Due to a few setbacks, there was not enough data obtained to get a good estimate of the turtle population. But all was not lost. We marked 213 turtles, 173 of which were adult female Northern Map turtles. This information tells us that there are at least that many adult females which is pretty amazing - especially considering females do not mature until about 10 years old! It also helped us to identify individual females and their habits, including nesting site choice. It has also confirmed that many turtles nest at least twice in a season. I hope to be able to do more with this data in the future.

What now?

My official research on hatchling emergence is done for now. My colleagues and I placed nest boxes on new nests again this year but they are notched to allow hatchling escape and so I am not monitoring emergence timing. However, myself, FKIH and Turtles Kingston want to work together going forward to keep helping the turtles at this location. These turtles are under a lot of pressure from development in the area in addition to all the other risks that turtles are facing across the board.

In the 2022 nesting season (June and early July) we are looking for volunteers to help with nest boxes, training will be provided - let us know if interested and stay tuned for more in the spring. You can also sign up to be a Turtles Kingston member.