As part of our Tools and Tech to Save Iguanas year-end fundraising campaign, we asked some iguana conservation researchers to share their experiences in the field—and how important their equipment is to what they do. They had some great stories to relate!
If you’d like to donate to our Tools and Tech to Save Iguanas campaign to help fund field conservationists please click here. Thank you!
Finding Hidden Treasures in the Swamp
By Daisy Maryon, Researcher, Kanahau Iguana Research Station, Utila, Honduras
Hi, I’m Daisy, a researcher working in Utila island, Honduras to protect the Critically Endangered Utila Spiny-tailed Iguana—or Swamper as it’s known locally in Utila, because it lives in the mangrove swamps. We collect data on the Swamper with a method known as “capture – mark – recapture.” In this process, we locate an iguana, catch it up and record its size, weight, and general health, and then mark it with an identification tag. We will then be able to track the iguana and record its movements, and we can find it again after a time to see how it is doing. This method allows us to gather long-term population, natural history, and health data on this very endangered species.
Because our field site is the mangrove swamps, we need to get there by boat or kayak. We spend a hot morning surveying for iguanas with telemetry equipment to find a spot to begin the day’s data collection. If we’re lucky, we find a dry spot on the sand to sit. If not, it’s standing or sitting in the mangrove roots. But hey, it’s all in the name of science!
Upon finding iguanas, we weigh the animals in pillowcases or breathable cotton bags using pesola scales of different measurements. We have different size scales for iguana hatchlings, juveniles, and adults, which enables us to collect the most accurate data. After weighing, we carefully remove the iguana from the bag and use a tape measure or digital caliper to take the length of the body (the snout to vent length, SVL) in millimeters, and then the tail length (TL) separately. Iguanas drop their tails as a defense mechanism, and they are able regrow them, so we measure any regrowth separately. This can give us insight into areas where they may be facing more predation or poaching attempts. We write all the data we gather in waterproof notebooks. It’s very wet in the mangroves!
The next step is to mark the iguana with both a PIT tag (Passive Integrated Transponder tag) and a bead tag. The PIT tag works the same way as a microchip in a pet dog or cat: each animal has a unique number read by a PIT tag reader, which reads the radio frequency within the tag. The PIT tag is placed under the skin using a specialized needle. The bead tag is a small piercing in the nape of the neck, under the Swamper’s dorsal spines. It’s similar to a person getting an ear pierced. We use a clean needle and thread through plastic-coated wire with two or more beads attached. The beads are a unique color combination for each animal. Using these two methods, the next time we survey we can use both the PIT tag and bead tag to identify them and see any differences in weight or length.
When we do more specialized surveys, we need different types of equipment, to look at parasites in the blood, for example. We do all our usual data collection as well as using syringes to collect blood samples and microscopes to look at the parasites. When the Swampers are in breeding season, we take an extra step and use a portable ultrasound machine to look at the number of eggs and developing follicles inside the females.
Without the use of specialist equipment provided by IIF and their grants, we would not be able to carry out this important conservation work on this Critically Endangered species. We thank you for your support!
