Turtle Population Surveys
Wild Toledo is evaluating local turtle populations in the Toledo-area wooded areas and marshes through mark recapture techniques with painted turtles, common snapping turtles, spotted turtles and Blanding’s turtles. This data will allow Wild Toledo biologists to determine the population health of these species by providing insight on size, weight and number of turtles in each study location.
Left: Biologists also use radiotelemetry to find turtles in their environment. Turtles are previously caught and are outfitted with a transmitter and released back in to their habitat. They are then tracked once a week to see how they are using that habitat. The transmitter is harmlessly attached to the shell with an epoxy that can be removed later on. The antennae is situated behind the turtle and is flexible to allow the turtle to move unrestricted.
Blanding’s turtles are a state-threatened species that has been doing poorly around the U.S. and in the northwest Ohio area. In order to study these populations, the Wild Toledo staff uses several techniques to monitor the turtle’s population.
One method, mark recapture, involves catching the turtle and marking the shell so that when the turtle is recaptured later, biologists know whether that animal was caught earlier. This allows analysis of how the turtle is growing and how often it is caught in a certain area, shedding light on how many turtles might exist in that particular ecosystem.
Another method is to place a microchip, called a PIT tag, under the turtle’s skin. When scanned, the tag produces a unique identification number which allows Wild Toledo biologists to track the population similar to that of the mark recapture method.
A third method, used to study Blanding’s turtles, is global positioning satellite (GPS) and radiotelemetry. By placing a radio transmitter on the turtle’s shell, biologists can go out into the habitats of the Blanding’s turtles and track their location. Once found, the GPS transmitter can be collected and downloaded onto a computer to assess the turtle’s use of an ecosystem.
The Blanding’s turtle is very long-lived animal, making it difficult to obtain data, so research projects like this one must occur over many years to get accurate data. The size data we receive can be graphed which will allow biologists to determine age of the turtles which is important for understanding the dynamics of the turtle population. By supporting the Toledo Zoo, you are supporting Ohio’s native turtles.
Long lived turtles that prefer marshland and flooded forest ecosystems. They are omnivores and feed on aquatic plant matter and inverts and are characterized by their bright yellow chin contrasting with their dark brown shell.
Common throughout Ohio and often observed basking on logs and banks of ponds, drainage ditches and creeks, the painted turtle gets its name from the bright yellow coloration on its face and neck. The shell is relatively flat compared to the Blanding’s turtle. Males have very long front nails and the cloaca extends beyond the shell on the turtle’s tail.
The spotted turtle gets its name from the small yellow spots all over its shell. This turtle is black and, compared to other Ohio turtles, on the small side. The species is semi-aquatic, meaning that it spends some of its time on land as well as in the water. Spotted turtles are omnivorous, eating mainly insect larvae and plant material.
Common snapping turtle
Compared to other Ohio turtles, a mature snapping turtle is very large and is usually seen near ponds, lakes and other bodies of water. The snapping turtle hunts by sitting motionless on the bottom of a body of water and using a lure on its tongue to get small fish to go after the bait. Then the turtle snaps its jaws over the prey and eats it.
What we are learning
For the past eight years, the Toledo Zoo has been collecting data on Ohio native turtles and we are starting to learn about where these turtles overwinter. By using GPS technology, we can determine which habitats the turtles are more frequently using which will, in turn, allow us to figure out how to better manage those areas. With the mark recapture studies, we are starting to understand the size of the turtle populations in certain areas. By comparing the frequency of captures for particular individuals, we can start to get an idea of how many other turtles are part of the population.