The bulk of the work for the last few weeks has been collecting and processing as many lizards as we can catch. Over 400 in fact which may sound a lot but we actually wanted nearly 700-800 by this point with a total of 1200. But it seems we are going to fall very short of that mark, especially as our collaborators from Georgia Southern are leaving in a few days. The reason behind our struggles? Well imagine having to look for a 4cm brown lizard (see image below) in an almost infinite Jungle, not only that but it spends its time on brown branches under leaves. So you can imagine that it is pretty difficult to see them at the best of times. But it also seems they are in much lower numbers than they were a few years ago when my supervisor conducted a reconnaissance of the area. Population cycles like this are perfectly normal, predator prey interactions, food availability and temperature all play a part in population declines and increases. Its not just a species going to extinction. See classic examples such as Lynx and Hare population dynamics, which was always the quintessential case study during my undergraduate Zoology degree.
But back to the point, it seems like the population (from an anecdotal perspective) is lower than it was a year or two ago. Which means we are not getting the number of lizards we wanted when we go out to catch them. Instead of 100 in a day (Which is what we expected) its closer to 60-80 over 2 days. Apart from the one day where we caught 80 in a day. But there in lies the other problem. The weather. A very small lizard is hugely dependent on the weather. Lizards maintain their body temperature by utilizing the temperature of the environment. In places like the UK and Europe Lizards need to devote a lot of time basking in the sun or laying on warm rocks to heat their body. In the tropics this is mostly unnecessary due to the night time temperatures often being above 24 degrees. But even a few degrees change can alter everything (the whole premise of my PhD). When the stars aligned and we got the right mix of temperature, humidity and sun exposure we were able to get 80 lizards in one day. But for the last two sessions we were not in the gods favour. Too much rain got us the first time and the last two days before our collaborators leave were stinking hot causing many of the lizards to be in hiding or very hyper (hotter the lizard is the more energy it has, to a certain degree. Too much heat = DEATH). This hyperactivity makes them very hard to catch if they are out in these hotter days. So basically we are not getting as many lizards as we want and we are running out of time because all the lizards need to be taken to the lab for two days to get physical data from them. Meaning the project has to be scaled back from 100 Lizards on 12 islands to 100 Lizards on 6 islands. Not ideal, but that's unfortunately how it goes with fieldwork. I should have followed my own advice. Assume nothing, expect everything.
But best laid plans and all that. Time to make the best of the situation!
Derby's Woolly Opossum (Caluromys derbianus)
Northern Tamandua (Tamandua mexicana)
Great Tinamou (Tinamus major)