Baby Guenther’s geckos hatch on the Paradise Island - Ile aux Aigrettes

By Dany Vencatasamy - Mauritian Wildlife Foundation

As I came back to Ile aux Aigrettes for a couple of days in the 3rd week of December, from island trips with the reptile team to Gunner’s Quoin and Round Island, my first thought was to check all the Guenther’s gecko eggs that were remaining to hatch. Of the 36 eggs that had been laid 15 had already hatched and one juvenile Guenther’s gecko was observed. I also found another 13 eggs.

In January 2011, I spent a lot of time searching in new areas on the island during the day and at night. At night the white eggs are easier to spot by torchlight against the pale bark of the trees the geckos are selecting to glue their eggs. These efforts paid off as I found an additional 29 eggs. The first breeding season has been very successful, the release of 30 female and 20 male geckos (see previous blogs), has led to the establishment of 30 nest sites containing a combined total of 103 eggs. To date 52 eggs have already hatched and therefore has more than doubled the number of geckos on the 26 ha island.

I monitor each nest site every two days, which is now quite time consuming as they are spread across the central part of the island. I check on each egg, which I have labelled with a pencil and allows me to keep track of when it was found and when and if it hatches. Currently the eggs take approximately 66 days to hatch. To date we have found no evidence of predation by species like the introduced Mynah Bird. Details about the substrate (tree species, tree height, perch surface, perch diameter) and the eggs (nest site, number of eggs, height) are noted and the location of each site is georeferenced. The collection of this information will be used to compare to the reproductive success of the geckos on Round Island. One nest site consists of 13 eggs, which I believe have been laid by the two females that live in the vicinity, demonstrating the communal nesting behaviour that is seen in the other Mauritian day gecko species and on Round Island.

My search effort has now switched from looking for eggs to looking for baby geckos. Searching for and detecting the small grey brown juveniles within the dense forest is going to be really challenging, particularly after they disperse from their hatch sites. However, searching in the areas where they have recently hatched I have managed to locate twelve individuals. Most of them were observed on the same tree where they had hatched the same day or the day before, but some observations were also made in areas there were no eggs found; this tells us there may be eggs that we did not locate or that juveniles can disperse quite quickly from their hatch site. Being able to relocate individual juvenile geckos will be important to see how fast they grow and to also determine whether they survive. Knowing this will be really important for predicting the establishment of the geckos on Ile aux Aigrettes and to show that with some effort we can enhance the survival of an endangered species, despite the high rate of biodiversity degradation within the region.

Fortunately the majority of eggs have hatched without any cyclones, but survived the searing heat during a severe drought over the past two months. Now the rains have come in the form of an anticyclone, but we also have a tropical storm to the north and another depression forming off the north east of Mauritius. It may therefore be a turbulent start to the lives of these little geckos.