Anole Annals

My favorite brand of binos for lizard watching are steeply discounted right now. In optics–binoculars, cameras, etc.–you get what you pay for: more expensive units are generally of higher quality. Nevertheless, there’s a sweet spot that maximizes your bang for the buck, and that sweet spot in binos, I contend, is Eagle optics 8×32. Normally retailing at $380 or so, these have high quality lens and a good feel in the hand. And, most importantly, they can focus on lizards three feet away! Many binoculars are made for bird watchers and can’t focus anywhere near that close, making them not useful for looking at small objects such as lizards. And now the good news: the glasses are currently discounted to $239. Get ’em while the supplies last! You might also consider the 10×32’s. They don’t focus as close–a respectable 8′ according to the specs–but they do give greater magnification. And they’re more than half off.

Photo by Jim Ackerman

AA correspondent Liam Revell reports from Puerto Rico:

For the past three weeks I have been running an activity with Jim Ackerman’s integrative ecology laboratory students that Jim has dubbed (perhaps with a touch of irony) the Great Anole Survey. The objective of this survey is to measure the species richness of anoles (three, it turns out) and the population density of the most common species (the Puerto Rican crested anole, Anolis cristatellus) in a small urban forest called Bosque Centenario on the Río Piedras campus of the University of Puerto Rico here in San Juan, Puerto Rico.

Over three capture sessions, with groups of students ranging between from about three to ten, we made 99 captures of 80 different adult male A. cristatellus in the 1.5 hectare area of Bosque Centenario. Bosque Centenario, as far as I can tell, is an abandoned, highly disturbed, open area or old sports field that consists of grassy area, some wetland, and patches of trees. Lizards were found mostly on trees, but were also observed using concrete and various PVC pipes as perches.

Our data collection ended last Friday, but we finally ran the numbers today. We used two methods to estimate the population size within this open forest patch. Due to variability in our collection effort by day, we first pooled sessions 1 & 2 into a single “marking” session in which 53 distinct animals were marked. We then treated the 3^rd session, with 40 captures including 13 marked animals, as the “recapture” session and estimated the population size of adult males from these two numbers with the Petersen method (analysis 1). We also used only sessions 2 & 3 with the Petersen method (analysis 2), and finally the Schnabel method with all three mark and capture sessions (analysis 3).

By the Petersen method in analysis 1, we obtained a population size estimate of 157.1 (95% CI: 111.6, 235.6). In analysis 2, also using the Petersen method but with only data from mark & recapture sessions 2 & 3, we obtained a highly similar estimate, but with broader confidence limits, of N = 163.0 (114.7, 286.7). Finally, by the Schnabel method and using data from all three sampling sessions, we obtained an estimate of N = 147.8 (100.3, 255.3).

Given that this population estimate is from an area that Google Maps area calculator’s suggests is no more than about 1.5 hectares in size, this is quite an impressive number. The only prior study to quantitatively estimate population density of Anolis cristatellus in its native range is Genet (2002), and they found maximum densities of 68.0 male Anolis cristatellus per hectare – well below our lowest estimate of 147 individuals in 1.5 hectares, or about 98 adult males per hectare. That study also obtained population density estimates for juveniles and females, which they found to be significantly more dense than males – and I would guess that this is also true of our site (although we didn’t measure it).

Finally, some potential limitations include the fact that the Schnabel & Petersen estimators both assume a closed population. Our population is technically ‘open’ – but anyone that has studied adult male A. cristatellus knows that in the span of a few weeks, adult males are not going very far! We no doubt violated other assumptions of the method with our sampling protocol, but I will note that we marked 80 unique adult males in 1.5 hectares, and plenty of unmarked animals remained – so 150 in the whole plot seems more than reasonable, if not conservative.

For the record, the other two anoles we found in Bosque Centenario were Anolis pulchellus and the adaptable generalist A. stratulus.

This unusual anole was spotted in my backyard in Miami, Florida (West Kendall area) on 16 March 2015. I’ve never seen a green anole this ornate with such a prominent nape crest, blue spotting, blue eye ring, and scapular spot! There were two males pumped up full of testosterone displaying and chasing each other in a stand of bamboo. Could this be a species other than A. carolinensis? Or maybe it’s a “high blue” green anole. In any case, it was a spectacular find for the day 🙂

Seen in Miami, FL 16 March 2015 by Marc Kramer DVM.

Way cool. Check out it her. Based on actual research by Louie Yang and colleagues at UC-Davis.

Here’s the press release about it:

Budding Biologist™’s Lizard Island™ is a fun and scientifically accurate video game for K-5 players to teach observation, measurement and reasoning skills. Lizard Island™ teaches students about ecology by allowing them to catch and tag lizards as they explore multiple islands in the Bahamas.  Kayaking from one island to the next, players must capture, mark and measure all the lizards on the island. As players search for lizards, they see the rich biodiversity on each island and can click on plants and animals for more information.  Advancing through the levels leads to larger, more complex islands to explore and glean data from.

 Based on 30 years of scientific data collected from microislands in the Bahamas the game draws upon research and photographs from scientists at the University of California-Davis. Katy Castronovo, the artist, has combined island photographs with her own artwork to create plant and animal life on the island, including hermit crabs, buttonwood plants, pearl necklace plants, and joewoods.  Programmer Walter Hsiao portrays the lizards as realistically as possible in terms of breathing and movement.  Lizards have subtle size and pattern changes to help players understand differences among animals of the same species.

Players have three choices for catching lizards.  They can use one finger to draw a complete circle around the lizard, they can use a lasso, which works by tilting the tablet in order to get the loop of the lasso around the lizard or they can use their limited number of photos to grab a picture of a sly lizard that is hard to catch.  Players must be careful not to scare the lizard with movements that are either too fast or too slow, and the more time a player spends trying to catch an individual lizard, the more the lizard become skittish. Lizards can only be caught if the player is zoomed all the way in, accomplished by using two fingers and spreading them apart.  To have a view of the island as a whole, players can use two fingers to pinch together and zoom out.  Zooming out gives players a sense of the size of the island and gives clues for where the lizards may be hiding, since they are often found under plants.

A bar along the bottom of the screen fills with color as a player catches more lizards, so players can guess how far along they are for their level.  The number of lizards increases as players reach higher levels.  Once a lizard is caught, the player discovers information about the lizard, such as sex and health.   Players measure the lizard themselves so they can compare sizes of lizards on different islands. Players then tag the lizard by selecting a paint color that appears on the lizard’s back. Players will have the ability to view statistics about the lizards they have caught: how many on each island, the sex of the lizards, lizard sizes, and lizard territories. They record this data in their field notebook, as well as facts and observations about the lizards.  Players can also observe and learn about the other plants, animals and insects. They can record these observations and the facts they learn about the other organisms in their field notebook. For added fun, the longer the player spends on the island, the more likely they are to get pooped on by a bird flying overhead!

Parasitologist and herpetologist extraordinaire Susan Perkins is featured on the American Museum of Natural History’s website. Included are two podcasts in which she discusses fieldwork on the leopard anole, Anolis sabanus. Hear her discuss malaria, giant cockroaches, karaoke and the rigors of fieldwork on a tiny island.

Photo from Daffodil’s Photo Blog

This is the same lizard featured last week on Daffodil’s Blog eating a spider. Now it’s nomming something else, and photographer Karen Cusick doesn’t know what. Any thoughts?

Photo by Karen Cusick.

Karen Cusick watched this brown anole down a tasty arachnid. Read all about it on Daffodil’s Photo Blog.

And here’s another lovely shot of the so-called festive anole from Karen’s post.

Photo by Karen Cusick