Monday, May 31, 2010

Latest movements of the "Big Three"

The three large tortoises equipped with satellite tags have been reporting daily since release. The tags seem to be working beautifully. These are the animals that report directly via satellite so we can watch them move over the internet. The other 36 tortoises, like Klever, can only be found by Elizabeth et al. stumping around the brush tracking them with telemetry equipment. Below are traces of the locations reported from liberation site to the location today a week and a half later. The first image is the movements of the three from their release site overlain upon Google Earth imagery. The next image is of the same movements but placed upon 40 m contour lines. Some of the tortoises have made some dramatic daily moves of 100 m or move, then spend days at the same point. One tortoise went 300 m upslope and then returned downslope, apparently relocating to the very same spot several days later. These animals are settling into their new habitat, no doubt adjusting to a great abundance of new types of food (I suspect some of stops after days of roaming are "downtimes" for facilitating digestion). We will revisit these movements after 10 days when we get back from Espanola (more on that shortly) and see what these tortoises have been up to...

- James Gibbs, Santa Cruz Island

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