Giant escape artists finally free to roam Ile aux Aigrettes once again

It has now been over a month since we penned the Aldabra giant tortoises on Ile aux Aigrettes. This prevented them trampling and eating the poison bait that we placed 21 days ago to eradicate an introduced population of rats. With no rat signs for a while now we have removed the poison leaving only peanut oil flavoured chew sticks and baited live traps across the eradication grid, which we check and manage daily.

Without poison on the island and hopefully no more rats (see the last blog entry) there is nothing to stop us releasing the tortoises so that they can roam the island once again. It has been a tough few weeks of work in appalling weather conditions. The toughest part of the job was walking past our makeshift tortoise pens that each housed a few tortoises. On walking by the tortoises would often lift their heads and follow you with sorrowful eyes uttering a few deep groans and sighs. If tortoises could look depressed, these guys were. Even with plenty of room to walk around, ample basking spots under the ebony canopy and food and water served daily, it was clear that they wanted to be out.

Some were so keen to make their break to freedom that they tried all sorts of escape tactics. Many tried walking the perimeter with one foreleg constantly pressing the wire searching for (and creating) weak points. Some even walked around the fence at a 45 degree angle (sometimes almost vertical), like an unbelievably slow stunt bike on a wall of death, but this looked more like good fun than an escape plan. A few attempted to tunnel underneath although this tactic was quickly abandoned, because in most places the soil is very shallow on the underlying bedrock.

If you cannot go under then why not go over? This tactic was tried repeatedly by our oldest tortoise George. Although penned with three females, George was not a happy chap and craved the attention of people rather than his own kind. Because of his colossal size he could stand on his back legs and tower over the top of the fence, which was over a meter high. The trouble was that he just could not get his centre of balance to actually make it over the top. Obviously thinking it through, George would wait until two or all three females would group together next to the edge of the fence and then start to climb on top of them to get a better position. It would have worked had we not been at the house to coax him down with a bowl of water. He tried this too many times and being worried he may hurt himself; we decided to issue him early parole. Knowing that George would stay close to the house or on the main path we knew he would not be too much of a problem and could shift our poison stations out of his way or reach. George was therefore released on day 16 when we halved the amount of poison on the island and true to the rules of his parole he stayed close to the house and near the Pink Pigeon Viewpoint on the main path.

The bulldozer tactic was the most common; simply tuck your head in and just keep on walking until all the supporting wire, piled rocks, poles and vegetation snapped, bent, toppled or pinged out the ground leaving the wire fence mangled and stretched. We had one small female that was an expert bulldozer and escaped from the pen five times creating an exit for her co-conspirators. We spent hours trying to create “Fort Knox”, but still she kept finding her way out. Unfortunately for the tortoises, they had not devised an effective getaway plan and were always found within 15m of the pen happily snoozing away or munching away on a tasty plant.

It was therefore with a huge sigh of relief from us all, and the tortoises, to be able to set them free. Some were at the fence as we snipped through the supporting wires and helped push the fence out the way, as if they had an urgent appointment to attend. Others just sat there in bewilderment for a little while and had to be coaxed out of the way with food and water so that we could roll up the wire for storage.

Within a day the tortoises had found their favourite spots across the island and we were back walking the lines, searching for rat sign.

By day 26 we decide to stop the intensive searching. It had been 16 days since we last had any signs of rats on the island and we desperately needed to continue our usual reptile work on the other offshore islands that had been put on hold. It was decided that three of us should spend the next week on a neighbouring island, Ile aux Fouquets, to monitor a newly established population of highly endangered skinks, that we reintroduced a couple of years back. One of the team would stay behind on Ile aux Aigrettes to work on the Telfair’s skinks, walk the entire grid over the week to check the chew sticks and manage the live traps for the last time. The other team member would spend the next week in the rat infested forests on the mainland to test our new arsenal of home-made, non-toxic, wax blocks. If they work we plan to deploy them across the entire grid on Ile aux Aigrettes in January 2010, as one final check to ensure the island is clear of our little furry foe.

Before we depart with our new tasks, we have day 27, our first day without walking the lines and our first day off since we started 39 days ago.