Remember that scene in Honey I Shrunk the Kids where Rick Moranis is lost in the back yard? The blades of grass seem like skyscrapers and a passing ant is an enormous and terrifying monster. I couldn’t help but imagine this scene at the Discovering Wildlife Lecture Series when Dan Rosenberg of the Oregon Wildlife Institute described his study that tracks the movements of hatchling turtles.
You read that right – he tracks baby turtles.
He does it using radio-telemetry. Maybe you’re familiar with it. It’s the process of capturing an animal and attaching a radio frequency to it, by collar, tag, or wire, and then tracking its movements with an antenna. It works just like the radio in your car, where each station, or in this case each turtle puts out a unique frequency once outfitted with a transmitter. All you have to do is tune in to find out where it is. It’s a common practice among wildlife biologists to learn more about how animals use their habitat.
It’s what allowed us to follow the wolf OR-7 along his 700-mile walk from Oregon to California. It’s what the biologists are using to track the reintroduced bull trout in the Clackamas River. And for tracking something the size of a shrunken Rick Moranis, it’s super helpful.
Maybe we shouldn’t be surprised that Rosenberg is using radio-telemetry to track Oregon’s native turtles because our turtles are in a world of trouble.
Half of the 320 species of turtles in the world are endangered. Only two species are native to Oregon – the western pond turtle and the western painted turtle – and both are listed in “critical” condition according the states sensitive species listing. There are many reasons for their decline, but perhaps the most significant factor is a loss of habitat – wetlands – that’s been disappearing with development.
Maybe with a better idea of how the turtles use these wetlands, where they build their nests, when they travel, and why they are declining, we stand a better chance of keeping the two native turtles we have.
This past winter Rosenberg and his research team set out to try to answer some of those questions. They searched for turtle nests at two sites in Portland and when they discovered a nest they erected a protective barrier around it. Come spring when the hatchlings busted out of their eggshells, Rosenberg and his team super glued .5-gram transmitters that are about the size of a watch battery to their carapace.
They followed the hatchlings to see how they moved from the nest toward water and created spatial maps using the data they received from the transmitters. Rosenberg showed us these maps at the lecture and we all laughed. It turns out that baby turtle journeys are pretty hilarious. The hatchlings traveled from nests to hide behind clumps of grass, beneath moss, and bushes to elude being spotted by possible predators. They’d go about 10 feet in a day. Their 50-yard journeys took upwards of 15 days. The maps made me start thinking about that scene from Honey I Shrunk the Kids. I began looking up at the towering blades of grass and for just a moment my backyard never seemed so big.