Volunteering in St Lucia: monitoring whiptails

By Edward Bell

When not working in the coastal dry forest looking for White-breasted Thrashers another role we have out here is the continued monitoring of the St Lucia Whiptail lizard Cnemidophorus vanzoi. The St Lucia Whiptail is found only on four offshore islands around the coast of St Lucia, it was believed to be found on the mainland but by the time of its discovery in the 1960’s it ended up restricted to two Islands off the south east coast of the island, Maria Major and Maria Minor. Durrell and St Lucia forestry Dept successfully implemented a translocation to Praslin Island just up the east coast in 1997 to try and ensure the survival of the population. It was the introduction and spread of invasive species such as rats, mongoose and cats which we assume led to the whiptail dieing out on the mainland – so the first which needed to be done when translocating this lizard was to remove any potential predators off the islands.

After Praslin Island, planning commenced on establishing another meta-population with the hopes that the whiptails future would be a little more secure with it spread out a little more. In 2008 another translocation occurred this time to Rat Island off the North West coast near to the capital Castries. Now to keep these islands safe for the whiptail we carry out regular checks of the islands.

The other week we went to Rat Island, the staff at the nearby Sandals hotel very kindly ferry us over to the island in one of their speedboats. Once there the first job is to check all the bait stations on the island and refill them with poison if necessary; this is our first line of defense against rats. After checking the bait stations we carry out a check of the island looking for signs of human activity, as humans visiting the islands can inadvertently introduce predators, and we also do a visual check of the population.
The following week I visited Praslin Island with Stephen Desmond from Forestry and Alan another of the volunteers, while the other volunteers checked up on Rat Island. We carried out the same duties checking and refilling the bait stations doing a check of the population which appeared to be doing very well as we saw a lot of males, females and juveniles without having to look too hard. Another of the residents of Praslin Island is Gymnophthalmus pleei and we got the opportunity to catch up and get a closer look at a few individuals.

This is ongoing work and we will be checking up on all the populations every few weeks and dealing with any potential problems that may arise, this week’s task is trying to make the bait boxes Hermit Crab proof as they keep eating the rat poison and there is the potential for them to pass this along a food chain. They are resourceful little creatures but we have been experimenting and making frequent trips to the hardware store so hopefully we shall triumph over these little crustaceans.