By Harrison Goldspiel, Biologist with the Giant Tortoise Restoration Initiative
Hiking around Santa Fe Island, one wonders what the tortoises, iguanas, and other creatures think of the humans who show up every year to see what’s transpiring. We punctuate their peaceful pace of life with a short and intense round on measurements: of tortoises, iguanas, cactus, vegetation and more. Then we depart and leave them again to their endeavors.
This particular trip represented one of many over four years returning to monitor Santa Fe Island, during which time several hundred juvenile, captive-reared tortoises have been released to the island. But it was my first expedition with Galapagos Conservancy, and I’m keen to share my impressions of my first exposure to this starkly beautiful yet austere island and the intense round of tasks we complete to understand “what’s going on.”
Our primary tasks for this trip, like on previous expeditions to Santa Fe, were to check on the status of the tortoise and cactus populations on the island. In addition, we installed an array of 60 wildlife cameras to monitor species on Santa Fe for years to come — all in only six days! Luckily, we had a large and determined crew to get the job done, including two volunteers and two scientists from Galapagos Conservancy, as well as three guards from the Galapagos National Park.
Every morning, after having our breakfast and coffee in camp, we split into groups to work on specific tasks. Most days, I worked with Jeffreys Málaga — a long-term guard with the National Park who has a keen eye for tortoises, their habitats, and the plants they feed upon. We searched near and far, across open rocky fields and dense cactus forests, counting, measuring, and weighing tortoises as we found them.
Every tortoise on Santa Fe has a small permanent identification chip, which allows us to monitor individuals over time and see how they are faring in their new home. In total, over three days of long surveys, we found 313 tortoises of the 549 that have been released on the island over the last four years. We used our mark-recapture data to calculate a quick estimate of the population size and were pleased to see the result: 545 tortoises (99% of the released population) are likely to be alive and well on Santa Fe. And soon enough, perhaps in 5-10 years, they’ll start breeding. To quote our Conservation Scientist, Dr. James Gibbs, from an earlier blog post, they still appear quite “fit, fat, and active.”
Back at camp each evening, we changed out of our field clothes, cooked up a big dinner, and ate in our dining pavilion sharing stories of our day in the field. All the while, the endemic (and very cute) Santa Fe rice rats scurried about our feet. They provided lively company until 8 short-eared owls arrived one night, and we saw few rats thereafter. As the dark settled in, we turned on a small solar-powered lantern, heated up some water for coffee and tea, and relaxed for a few hours before retiring to our tents for the evening.
An important job for the week was installing an array of cameras throughout the center of the island, where most of the tortoises reside. Seemingly simple, this task actually required much creativity, improvisation, and detective work. Using a GPS, we navigated to predetermined installation points, scanning the scene of each location for potential tortoise activity. I was amazed at Jeffreys’ ability to read the landscape for tortoise signs, tracing their tracks in the dirt and pointing out potential areas for feeding and refuge.
After finding our “target zone,” we’d find the nearest cactus tree (or occasionally, some large rocks) and attached a camera with a bit of wire, taking care to not prick our fingers with cactus spines. Then came the “walk test,” whereupon James appeared to imitate the mating dance of blue-footed boobies, shuffling up and down in front of the camera, crouched low to the ground, waving and kicking his feet with enthusiasm until the camera gave its approval with a flashing red light. If all goes well, these cameras will be taking pictures of tortoises, land iguanas, and other Santa Fe wildlife for many years to come, giving us a closer look at their distributions and interactions among species on the island.
Before I knew it, we accomplished all our objectives for the week and were hiking back down the canyon to the beach to load up the boat. We hope to be back on Santa Fe in a few months, bringing with us some sub-adult tortoises from Española that will help jumpstart breeding activity on the island. I’m excited to see what images of life our cameras have captured in our absence. Hopefully, we’ll have much to share.
Harrison Goldspiel is a biologist currently working with the Giant Tortoise Restoration Initiative in Galapagos. He holds a Master of Science from the State University of New York’s College of Environmental Science and Forestry.
All photos © H. Goldspiel / GTRI.
Read more findings from the 2019 Santa Fe monitoring trip.