So the primary goal this year was to walk the islands and catch as many of the remaining lizards as possible. With a complete census of the population, we can start getting awesome data on natural selection’s “filters” dictating survival of the fittest. Even better, by taking careful measurements of the survivors we can figure out how much they grew, and with DNA from the new recruits we can sort out a full family tree for each island. So exciting!
This post is video heavy so if you’re reading this on email right now, click over to the blog so you can see each of these steps in live action!
We spent the bulk of our time on the islands walking in-line about 2 m apart looking for lizards scooting out of a bush ahead of us. Patience and systematic searching is the key to getting a comprehensive population recapture, and while it was tough to repeatedly walk over the same lizard-less bushes over and over, it paid off. I don’t have any video of us on the comprehensive search – I was busy holding my spot in the line – but here’s a glimpse at the more random searching we’d do trying to scare up troublesome lizards that would go to ground when they heard the herd approaching.
That was Petalida, a delightful island for catching. It was all hand-catching work, but each grab was on a soft bed of fragrant herbs. Here’s mavronissi, the “black island” – razor sharp rocks and spiky bushes:
Luckily the scenery was beautiful. You can see in that video though the occasional pink flag. That’s where we caught each lizard and where we returned them after measuring.
Here’s a measuring video. We’re taking a whole lot of measurements of body size, head shape, and limb morphology. You can make out each in that video (though don’t feel compelled to watch the whole thing, it’s a bit boring. I tried putting in lightsaber sound effects for every move of the calipers but couldn’t quite get it working… I might try again because it was hilarious. For now, just imagine it). We have a lot of questions about how lizards might change their feeding ecology on small islands. That’s often directly related to how they handle food (head morphology) and how they catch it (limb morphology). We’re hoping that tracking these variables through time will give some unique insight into how these traits change on small islands.
The final step was PIT tagging the lizards so we can positively identify them into the future. I’ll show you a video of that in the next post.