Our first field week is over and we're off to a good start. Megan and I arrived in the dark at the Organization for Tropical Studies' Palo Verde Research Station, Palo Verde National Park, after a long travel day on January 18th. We ate a vry late dinner, provided some mosquitos with a meal, and went to bed.
We spent the next day getting our processing lab assembled, settling our rooms, and scoping out resident iguanas such as Kaplan, the largest male at the station. Marked in 2013, he still sports his original beads, Blue-Yellow-Brown. As mating season is in full swing, Kaplan is bold, making important circuits in his home range, chasing off male interlopers, and copulating with females.
Our next reentry into the field is the process of trapping iguanas, checking them for PIT tags, and rebeading if they are a known animal. If the lizard is new, we take standard morphometric measurements, a blood sample for molecular analysis, especially genetic relatedness, and assign a bead code. Important for our work is monitoring the stability of the social group (very) and seeing in what ways an animal has changed its routine, moved refuges, or otherwise is behaving differently than August 2015.
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| Rebeaded White-Yellow-Black |
Since 2013, more than 110 lizards have been caught and beaded in the research station. We track how many new animals we see per day to understand how long it takes to observe a large majority of marked animals. It's a natural expectation that some animals will disappear through predation or emigration. Likewise, younger animals are establishing refuges within certain areas while males are more evident as they seek resident females. Adults males sometimes immigrate into the area. And, lizards move to different refugia within the site.
For example, last July and August, White-Yellow-Black (WYK) used a pipe to sleep in right in front of the OTS office. This trip she is no longer using that pipe and has only been observed in a small woods patch in front of the researcher dorm, about 15 meters away from the office. This may be a temporary or permanent refuge change; we don't know. On the other hand, this is not a large move and WYK is interacting with the most of the same animals from the July-August 2015 observation period.
When we see a move such as WYK we also try to find the refuge as this is the place where we may quickly check each day to see the animals is still in the group. It's rather helpful that Ctenosaura similis is routinized!
