The Anegada iguana is a critically endangered species of iguana. As the name suggests, it is endemic to the small island of Anegada, one of the British Virgin Islands with a sparse human population. A large part of the disappearance of this species is due to the overwhelming presence of feral cats that prey upon the juvenile iguanas.
Since 1998, the Fort Worth Zoo has worked to spearhead a headstart program for the Anegada iguana with its in-country partner, the National Parks Trust of the Virgin Islands. When the project started, there were between 200 and 300 individuals on the island. One of the Zoo’s conservationists, Kelly, is on the island for nearly four months each year locating iguana nests, relocating hatchlings, reintroducing and monitoring headstarted iguana, training students and holding an annual community-wide iguana festival.
The Anegada iguana recovery program focuses on finding nests and relocating hatchlings to the headstart facility. The recovered iguanas grow at the facility until they are large enough for feral cats to not be a threat anymore – about three years.
The recovery process starts with locating the nest. The iguanas lay their eggs in chambers buried beneath the sand. The female digs a tunnel until she finds the right temperature and humidity to lay her eggs. She then digs a chamber and lays her eggs within. She seals the chamber, climbs out the same tunnel and pushes sand into the entrance of the tunnel to close it off. When the eggs hatch about 90 days later, the hatchlings dig straight up from the chamber. When it comes to finding the nests, the team looks for horseshoe-shaped disturbances in the sand with sticks and leaves half buried within. Kelly then digs into the tunnel to estimate the position of the chamber so that a metal fence can be placed around it to later collect the hatchlings and transport them to the headstart facility.
The horseshoe shape and disturbed sand pictured here is likely an entrance to an iguana nest.
This year, Kelly decided to train a new conservation partner. Pena is a 4-year-old scent detection dog that was donated to Kelly by a professional dog trainer named Paul Bunker of Chiron K9. Kelly and Paul have been working together to train Pena to use scent detection to find iguana nests in the wild. Kelly brought sand from an iguana nest back to Texas to help train Pena prior to their first trip together. Kelly and Pena spent seven weeks in Anegada this summer, with help from Paul for two weeks, tracking down nests and putting Pena’s skills to test.
Meet Pena, the newest Anegada iguana conservation partner. She wears these boots to protect her feet from the thorny brush and hot sand.
Scent detection is a team effort. Kelly walks with Pena in a way that gives her the most opportunities to cross the scent. They start downwind and zigzag through the area to allow her to cross the scent more than once. Not only did Pena likely find an iguana nest (although the team is confident, we won’t know for certain until Kelly returns this fall to find the hatchlings), but she also found a wild iguana, too!
Kelly and the rest of the team are feeling very optimistic about Pena’s abilities. Her scent-detection adds another layer of certainty to the team’s discoveries. After a little more practice finding nests, Kelly and Paul plan to train her to find hatchlings next.
The program is expecting to release its 300th iguana soon, which means the wild population has doubled with the Zoo’s efforts! We are excited to see Pena’s impact on the project, and we look forward to more updates when Kelly and Pena travel back to Anegada this fall to collect the hatchlings.