Why was the Oakland Zoo at the 4th Annual Beaver Festival in Martinez? No, the Zoo doesn’t have beavers, but it does have Western Pond Turtles which rely on beaver habitat. The event was a wonderful opportunity to create awareness about the Zoo’s Western Pond Turtle Head Start Program and the conservation efforts involved to protect the only aquatic turtle native to California. The Oakland Zoo along with many other environmental organizations participated in this festival to create awareness about native species in the Bay Area and the fragile ecosystems where the animals live.
In October of 2007 several beavers took up residence in Alhambra Creek, which is in the downtown area of Martinez, and this caused a controversy. Immediately, members of the community felt strongly about keeping the habitat intact and finding a way to co-exist with the beavers. However, the dam was reported to pose a flooding hazard and the animals were scheduled to be eradicated. Concerned residents took action and formed a non-profit organization “Worth a dam” to help maintain the population of beavers in Martinez through education and practicing humane environmentalism. A special flow device was installed in the creek to manage the dam and the outcome was a success!
Beavers are a “Keystone species” in North America because they play a critical role in biodiversity and many species rely on beaver ponds for survival. The Western Pond Turtle will use beaver burrows and lodges to seek refuge, and the ponds provide a rich source of food for turtles, because they attract frogs, fish, and insects.
Oakland Zoo Docent Cindy Margulis and I brought “Dilbert,” the Zoo’s non-releasable turtle ambassador to the festival. Dilbert was a hit, teaching people about the importance of protecting Western Pond Turtles, which are a ‘species of special concern’ in California. What made the experience even more memorable for the kids was a “Keystone species” charm bracelet designed specifically for the festival. We gave each child a turtle charm when they came up to the Zoo’s booth. The children then told us about the relationship between beavers and turtles.
Cindy and I were really inspired to see how a small group of people can make a positive change. The Zoo’s Western Pond Turtle Head Start Program continues to be a success. Since 2008, Zoo staff, along with researchers from Sonoma State, have released eighty-one turtles back into the wild. The program is a joint effort with the San Francisco Zoo and Sonoma State that brings people together to help preserve a species and its habitat, so that future generations of have the opportunity to enjoy this magnificent aquatic turtle.
If you are interested in learning more about the Western Pond Turtle Head Start Program or other conservations projects, please visit our website at www.oaklandzoo.org.
Its turtling season at the Oakland Zoo again! Each summer our zookeepers team up with biologists and students from Sonoma State University to study the western pond turtle. Turtle nesting season is in full swing and California’s only native aquatic freshwater turtle has been an enigma to researchers for years. This is the fourth consecutive year that zookeepers have spent in Lake County and our knowledge of this species of special concern has increased exponentially. Here is just a short run down of a few of the things we have learned about western pond turtles through our collaborative research:
First, we were surprised to discover just how dry the nests were. Aquatic turtles are usually expected to have very moist nests, but not our western pond turtles. Based on our observations at the site, we created a very dry vermiculite mixture in which to incubate the eggs we collected. Several experts expressed concern about the lack of moisture in the mixture, but our guess was correct and we had a 90% hatch rate the first year.
One little known fact about many reptile species, western pond turtles included, is that the sex of the hatchling is determined by the temperature at which the egg is incubated. Along with our dry vermiculite mixture, we also set up five separate incubators at five different temperatures. The hatchlings were carefully marked with numbered dots so we knew exactly which clutch and incubator they came from. The hatchlings were then raised here at the zoo for about ten months, until they were big enough for a small endoscopic surgery to determine their sex. This data was then correlated with the incubation data and we now know the exact temperatures that produce male turtles versus female turtles.
As time went on, our project expanded and we also began to incubate nests in the field. This requires careful placement of high tech temperature and humidity sensors inside the nests and then covering the nests to secure them against predators. The wide range of temperatures in even a single day took us by surprise. Who would have guessed a difference of up to fifty degrees in one twenty-four hour period.
This is a project that is near and dear to our hearts, not only because it is a native species, but also because it is a project that zookeepers can be directly involved in. Just days ago, two keepers went to the lake to use telemetry equipment to track nesting females while other keepers were here at the zoo caring for last year’s hatchlings, who will be released at the end of this month. As we continue to progress in this conservation project, we hope to learn even more about this special animal.