Salt Creek Greenway Association
The Salt Creek Greenway
Purpose and Partners
Places to Visit
Special Greenway Projects
BLANDING'S TURTLE RECOVERY PROGRAM
by Dan Thompson
March 15, 2014
Blanding's turtle (Emydoidea blandingii) is considered endangered throughout much of its historic range which includes states around the Great Lakes region, provinces of Canada, Nova Scotia, a section of the East Coast and Nebraska and Minnesota. Efforts are underway in these geographic locations to save the turtle from heading into extinction.
The medium-sized Blanding's turtle is about seven to nine inches long and may live to be 80 years old. The dark colored carapace, or upper shell, is domed with flecks and streaks of yellow. The plastron, or lower shell, is yellow with dark symmetrical markings unique to each individual. No two are alike.
The head and legs of the turtle are dark with yellow mottling. The chin and throat are bright yellow.
The Blanding's turtle is semi-aquatic. The turtle prefers wetland habitats or marshy areas with shallow, stagnant water and vegetated uplands.
Turtles can hibernate for three to four months. Turtles overwinter on or in mud or vegetation or under or near water. During this brumation period, turtle metabolism slows. They do not eat and do not need to surface to breathe. They draw enough oxygen into their systems from the water they are submerged in to survive.
The Blanding's turtle is primarily a carnivore, eating snails and crayfish, frogs, tadpoles and fish but may also consume some plant material, crustaceans and other invertebrates but will also eat berries and vegetable debris.
It takes 14 to 20 years for the Blanding's turtle to reach maturity. Mating season occurs in April and into early May. The nesting season takes place throughout June. The turtles mate only once a year. Each female can produce an average of 12-13 eggs per clutch.
When the time comes for the female to lay her eggs, she hunts for a place to build her nest. She looks for well drained sandy or loamy soil. She prefers well drained soils with sparse vegetation areas, choosing forbs (native wildflowers) over grasses as cover. She digs the majority of her nest with her rear legs until the nest hollow is ready to receive her eggs. Each egg is carefully positioned by the female in the nest. Eggs are usually laid at night and the nesting process may take around three hours. She then covers the nest with the excavated soil and leaves.
Turtle parents play no role in caring for or raising their young during the hatching period or after the young are born. From the moment the eggs are laid, the baby turtles are on their own. It takes about 60 days for turtles to hatch. During the incubation period, 90% of turtle nests are destroyed by predators each year. This severe predation is the most serious threat to the survival of Blanding's turtles and one of the alarming reasons why the species is on the brink of extinction.
Raccoons are the most voracious predators of Blanding's turtle eggs and baby turtles. Other predators include the skunk, opossum and mink. The rising population numbers of these predators in many areas of the turtle's historic range is contributing to the loss of this species and why very few turtles hatch or reach adulthood.
Loss of habitat, collection by people and road kill are also factors in turtle mortality and the drastic reduction in population numbers.
Blanding's Turtle Survey
When naturalists and scientists realized that a dramatic decline in Blanding's Turtle populations was occurring throughout its historic range, it became obvious that an intervention was necessary to save the species.
A series of studies and surveys was undertaken to record population numbers and habitat locations throughout the turtle's range. The reports verified that turtle habitat was being destroyed and population numbers were crashing as predator populations grew out of control. There could be no doubt that the species was facing extinction.
in the county. Over time, a consortium of partners joined together to develop a strategy and coordinated plan to save the Blanding's turtle. Many agencies are now involved in this national and international effort to reverse turtle decline and loss and develop a protocol to increase and preserve turtle populations through human intervention.
The Role of DuPage County and the Illinois Department of Natural Resources in Saving the Blanding's Turtle
In 1987 - 1990: A survey of the turtle population was conducted in Illinois
In 1996: The Blanding's Turtle Head Starting Recovery Program began
In 1997: The Blanding's turtle was listed as a threatened species in Illinois
In 2009: The Blanding's turtle was listed as an endangered species in Illinois.
The Head Starting Program - Human Intervention to Save the Turtles
Pregnant females are collected in their natural habitats just before eggs are ready to be laid. Females are transported to the Willowbrook Wildlife Center in DuPage County where nurseries are in place to receive and incubate the eggs. Xrays are taken to determine the status and number of eggs each female will lay. Each female receives a number and is identified. The eggs she lays will also be numbered and recorded, connecting each mother with her eggs and hatchlings to be. This scientific record of each mother and her clutch of baby turtles establishes a data base of genetic information and DNA to carry on a successful breeding program.
After the female lays her eggs in the nursery and is ready to be released into her habitat in the wild, she is fitted with a radio transmitter. The transmitter does not damage her shell or restrict her ability to forage or swim. A new transmitter will be attached to her as the cycle repeats itself to collect and raise her eggs each year. Occasionally younger turtles will shed their transmitters as their shells grow.
Recovered eggs are placed into an incubator with the mother's ID written on each egg. Eggs are kept in trays of vermiculate in the incubators and are candled during the incubation period to monitor the development of turtles inside.
As the young turtles develop in their shells, they can communicate with each other.
Eggs are maintained in incubators at about 28.5 degrees C. This results in a mixture of male and female turtles developing.
Female turtles develop at temperatures kept at 30.5 degrees C. Male turtles develop at temperatures kept at 26.5 degrees C. Females hatch in about 50 days. Males hatch in about 57-60 days.
During the incubation period, the temperature is kept at the desired level and moisture content is monitored to maintain the precise wetness needed for turtles to remain hydrated before hatching. Since more females are needed for egg production, temperatures are selected to favor more baby female turtles being born.
It is important that young turtles do not imprint on their human caregivers to ensure that their inborn instincts to survive in the wild are not compromised. Otherwise, the turtles could not be released into their native habitats. Turtles kept in exhibits can weaken their instincts to survive in the wild.
Baby turtles are carnivorous at birth. They eat mosquito larvae, grubs and small fish and tadpoles. In captivity, they also are fed specifically prepared nutritional pellets.
After hatching, baby turtles are transferred to tub habitats for indoor rearing that mimic their native ecosystems.
Each hatchling is given a number and check-up at birth. This involves keeping a record of weight, gender, health and mother. Check-ups are given periodically during the indoor rearing phase.
When the turtles are about one year old, it is time for them to be released into their native habitats. This usually occurs in September or early October. The baby turtles are fitted with microchips, similar to microchips used for pets, to identify them and track their whereabouts and survival.
To date, over 2,000 turtles have been released since l996, and while mortality of these turtles is high naturally, there are a number of young subadult turtles now out in the population from this effort. We may only be a few years away from some of these turtles starting to reproduce.
Blanding's Turtle Recovery Partners
Forest Preserve District of DuPage County - Willowbrook Wildlife Center
Brookfield Zoo - Dragonfly Marsh - Forest Preserve District of Cook County
John G. Shedd Aquarium
Peggy Notebaert Nature Museum
Wheaton Park District - Cosley Zoo
University of Illinois
Northern Illinois University
Next Steps for the Head Starting Program
A series of next steps needs to be taken so that the Head Starting Program continues to succeed in order to ensure survival chances for the Blanding's turtle and preserve genetic diversity into the future:
1. Protect and restore turtle habitat throughout its historic range and enlarge and increase protected areas.
2. Improve wetlands and nesting areas.
3. Improve and protect turtle movement corridors
4. Reduce predator threats
5. Reduce road kill and mortality
6. Maximize egg collection numbers and indoor hatching, rearing and release numbers
7. Improve husbandry techniques
8. Add the Blanding's turtle to the Federal List of Endangered Species
For more information about the Blanding's Turtle and the Head Starting Program go to: http://www.dupageforest.com/Conservation/Managing Natural Resources/DuPage Plants and Wildlife/Amphibians and Reptiles/Turtles.aspx.
Blanding's turtle photos by Dan Thompson Presentation photo of Dan Thompson by Valerie Spale
|Return to Main Menu|