Tales from Galapagos

Hi everyone-

So, now that I've got this blogging thing down, I'm going to fill you in on the rest of my trip to the Galapagos. Hopefully, I'll even be able to put in some photos!

Like I said in my earlier email, I was helping my friend, Sarah, with her research on Darwin's finches. She is in her 3rd field season of PhD research on the medium ground finch (Geospiza fortis, I believe). She has been following a population of finches at Garrapatero, a national park on Santa Cruz Island. This population is bi-modal; in other words, there are finches with small beaks and finches with large beaks, but very few finches in the middle. Sarah is trying to determine whether these finches are mating assortatively, such that small finches mate only with small finches and large finches mate only with large finches. If that is the case, we might be seeing this one species evolving into two. So, I was helping Sarah figure out which males were mating with which females. We would first find nests by following birds or simply seeing them in the forest. Then, we would mistnet near that nest to capture both the male and female, band them, and take a blood sample from them. We checked nests to count eggs and/or hatchlings and once the hatchlings reached about 8 days old, we would remove them to take a blood sample and then put them back in the nest. Finches, like many birds, can have affairs on the side, so all of the nestlings in one nest are not necessarily from the male bird that built and is caring for the nest. The blood samples of nestlings will be used to determine parentage. And this is basically what I did with Sarah. We caught a cab at 5:30 each morning and worked from around 6 to 11 before taking a cab back to the Charles Darwin Research Station where we were staying.

This year was remarkable on Santa Cruz because the rains were late (early March) and plentiful, so the breeding season was much later than usual and also much more productive. In the past two years, Sarah only found about 5 nests each year. This year, we found more than 90! About 25 of those were just being built when I left, so Sarah will be checking those next week. The rest were nests we checked while I was there. The sad part of the whole thing is that very few of the eggs actually fledged. I think we found about 5 that fledged from the sixty-some odd nests. Most of the eggs hatched, but a nest parasite killed perhaps 60 or 70% of the birds. And many of the rest were predated by larger birds. The parasite was first seen in the Galapagos in the early 80's I believe, and is common in mainland Ecuador. Little is known about it's introduction to the islands or the current range. There are a few scientists who are beginning to study this parasite in the Galapagos, so hopefully we'll have more information in the next few years. (Note for all the scientists in the group: If there are any inaccuracies in this, it's probably because I have forgotten exactly what Sarah told me about her project and the Galapagos in general.... so don't quote me. It's probably better if you look it up yourself.)

Aside from working, I spent a lot of time reading in my hammock, snorkeling, enjoying the sunshine, trying to learn Spanish and appreciating my role as assistant (i.e. someone else tells me what to do and I have no responsibility). I went diving for a day with Sarah and saw a ray, a turtle, a dead shark (probably finned), stonefish, nudibranchs and lots of other fish/invertebrates. A highlight was definitely seeing sea lions- they're incredibly playful and friendly, not at all scared of people!

And that's all I have for my trip to the Galapagos. Hope you enjoy the pictures!

Haldre