Counting the giants of Cousin Island
Cousin's Aldabra giant tortoise population now numbers 75 individuals, according to the results of the 2021 census. This is the highest number recorded on Cousin Island since monitoring began. This is the third consecutive year that Aldabra giant tortoises have increased on Cousin.
Staff search the island and collect data on tortoises found
We have monitored the tortoise population on Cousin since 2011. We check on population size, breeding habits, and any potential impacts a larger population could have on the small granitic island, particularly on its vegetation. The 2021 census began in July and was concluded in December. Our staff searched the island's plateau, where many of the larger animals are found, and the hill, where sub-adults and juveniles are located, to find, mark, and collect data on the tortoises. Along with dedicated searching, staff, volunteers, and researchers kept an eye out for unmarked tortoises while on other activities. The staff conducted evening patrols to look for nesting females at three nesting locations where Aldabra giant tortoises frequently nest. No hatchlings were found, but a total of nine nests were recorded.
We have monitored the tortoise population on Cousin since 2011
It is an exciting activity to count tortoises, much like searching for treasure on an island. Despite Cousin's size, finding unmarked tortoises is both daunting and rewarding. A former CBC participant, Duncan, explains.
"One of these surprises I had on Cousin came when we set out to do the tortoise census. We woke up around 6 am to begin searching at 6.30 am. We were told that there were sightings of an unmarked tortoise that was said to be residing up the hill. I never knew how well tortoises could climb. We all geared up and started our trek up the hill to a picturesque summit with an absolutely stunning view of the entire island. We took a few minutes to bask in the beauty and truly take it all in. Shortly after we began our search. We spread out and each began sifting through the ferns and under the rocks to see if there were any traces of a tortoise. We had been searching for about an hour during which you feel like you’re an explorer in some uncharted area all in search of something you would normally consider quite slow. After about an hour we finally found a female tortoise. It was a triumphant feeling, even though this one had been previously tagged. We later found out that it had been nearly 3 years since this particular tortoise had been documented. We began to make our way down the hill and right next to our path down we found exactly what we were looking for, the unmarked tortoise! We all celebrated and began measuring and documenting it. Though I didn’t know what to expect from the tortoise census, it became one of my favourite experiences during the Conservation Boot Camp."
The Seychelles magpie robins often follow and feed on invertebrates exposed by moving tortoises
Tortoises are critical for small islands. Their grazing and trampling create open areas used by nesting seabirds. Grazing also aids in nutrient cycling and the dispersal of seeds around the island. The endangered Seychelles magpie robin frequently follows and feeds on invertebrates, which are exposed as the tortoises move. They are also some of the most loved animals on the island. And those like local celebrity George are not hard to find at all. They will be welcoming you on the beach.
