Reproductive and Dispersal Behaviour of the Critically Endangered Utila Spiny-tailed Iguana Ctenosaura bakeri, Honduras

Ctenosaura bakeri is a Critically Endangered iguana species endemic to the island of Utila, Honduras. It is known to occur throughout the island (41km²; extent of occurrence), although the area of occupancy is likely to be less than 25% of the island due to its association with mangrove habitats. This project began in January 2016, with fieldwork continuing until early September 2016. We aim to provide current estimates of population size using a combination of capture-mark-recapture methods and line transect surveys. Hybridisation with C. similis (Common Spiny-tailed Iguana) is a theorised threat to the species, so DNA samples are being collected from both species to investigate this and update a previous genetic study on these congeners (Pasachnik et al. 2009). Very little is known about the nesting behaviour of C. bakeri, and we are investigating this using radio telemetry. We have tracked gravid females to nesting sites with some surprising results, and gathered behavioural and home range data for both females and males. The mangrove inhabited by C. bakeri, as well as their nesting sites, are under threat from increasing tourism enterprises and economic development on the island. Hunting of all iguanas, including C. bakeri, is common throughout Utila, with gravid females being particularly highly prized. Observations of hunting were made almost daily at various field sites during the iguana’s breeding season (February-June). Questionnaires were given out in the community to investigate the local attitudes towards the iguana species, and sought to gain insight into hunting activity on the island. This species and its habitats require protection at a local level, with improved enforcement of existing anti-hunting legislation and increased and ecologically informed control of development. This project aims to contribute vital population and behavioural ecological data that will inform immediate and necessary action required for the effective conservation of this species.