Spotlight on Cuban Anoles, IV: Anolis allisoni


Anolis allisoni, close relative of our friendly neighborhood A. carolinensis, is a remarkable lizard. It’s also no stranger to Anole Annals, and the populations found off the coast of Honduras were just featured here. We saw a lot of these lizards in Cuba, and the post is pretty picture heavy, so join us after the jump for blue-headed lizards.

Continue reading Spotlight on Cuban Anoles, IV: Anolis allisoni

Blue Head, Pink Dewlap

…can mean only one thing: Anolis allisoni. I’ve been trawling through twitter today. Searching on “anole” is no longer useful–the term’s been hijacked by very exuberant tweeters talking about the comic book character’s latest sexploits, but a search on “Anolis” still yields dividends. Including a nice article, in Spanish, on A. allisoni from the Cayos Cochinos off the coast of Honduras (discussed previously on AA). Included are some nice photos, like the one above, and several videos.

Anole Performance Meta-analysis!

Example of a three-task Pareto front in a 3D morphospace, Figure 9 in Sheftel et al 2013.


I want all of your old performance data.

Who am I? I am a Ph.D. student and the thrust of my dissertation project is to arrive at a better understanding of how selection, trade-offs and constraints act on suites of performance traits, leading to adaptive phenotypic shifts in populations and, ultimately, evolutionary change. I am particularly interested in constraints imposed on performance evolution by intralocus sexual conflict, and in the relationship between preferred and maximal performance.

What am I going to do with it? I am conducting a meta-analysis of existing performance data, which involves mapping suites of performance traits onto lizard morphospace and fitting a multivariate response surface. This surface can then be used (by everyone!) to predict trade-offs between different types of performance traits in various selective contexts, and to identify regions of morphospace associated with performance peaks and valleys. These areas, and the taxa that occupy them, would thus be of interest in terms of looking for behavioral compensation or other solutions. Conversely, areas of morphospace devoid of extant taxa may be indicative of insurmountable constraints or something even more interesting. Such insights will, I hope, inform more exploratory, experimental and comparative avenues of investigations.

I’m focusing on Anolis in particular to start with, and I’d like to quantify the relationships between the span of extant anole morphology and any and all whole-organism performance traits. But to do this, I need data! Lots and lots of data! And I don’t have enough :( Which means I need your data.

What I need:

 Raw data1 from previously published studies involving performance trait data along with morphological2 measurements for any and all Anolis species would be very useful and much appreciated. The more coverage of morphospace/performance space, the more useful and powerful the model!

If you’ve ever measured any of the following performance traits in anoles, you’ll probably be getting a grovelling email from me, but just in case you have somehow escaped my scrutiny, or don’t want to wait for the grovelling email, here is what I am looking at:

  • bite force
  • sprint speed
  • acceleration
  • endurance
  • exertion
  • maneuverability
  • jumping
  • climbing
  • clinging

Performance data for multiple traits measured in the same individual will be the most informative, but I will also need plenty of data on single performance traits. I have few other standards (as far as this project goes), so anything will be useful!

Thanks so much for reading this far! I sincerely hope this piques your interest and inspires you to share your work with me. I will of course be open to discuss any and all aspects of data-sharing, collaboration and subsequent use or availability of the data. All contributing authors will be acknowledged and papers cited, or whatever else is necessary! If you have anything you would like to contribute please feel free to contact me directly @

1 I can use raw data files, in whatever format (e.g., .xls, .txt., .sys, .jpg of a lab notebook or rum-stained bar napkin).

2 I would be happy with anything from SVL-only to comprehensive measurements for individual limb components, toe pad area, etc. Body size and limb measurements are ideal!

(Figure from Sheftel, H., Shoval, O., Mayo, A., Alon, U. 2013. The Geometry of the Pareto front in biological phenotype space. Ecology and Evolution, 3(6): 1471-1483)

X-Ray Oddities in the Bahamas


We’re back in the Bahamas for our yearly trip monitoring evolution of brown anoles on small islands (most recently reported on a year ago).  These populations were hammered by Hurricanes Irene and Sandy in 2011 and 2012, and are just now recovering. Most exciting to us was one population reduced to two individuals, which seemed to disappear during the course of our visit last year. Had the population gone extinct? No–we’ve found 14 lizards there this far. Hooray.

Part of what we do is capture lizards, bring them back to the field lab, and x-ray them to measure their morphology, to see how morphology changes from one year to the next. And while doing so, we see all kinds of interesting anomalies. For example, check out the left hind leg of this female–she’s missing most of the toes on that foot. Turns out that that lizards lacking the full complement of digits is not very unusual (check out this post from several years ago on more severe mutilations).

But this year we’ve had some more unusual sightings. Check out the left knee of the male below. Clearly, he broke his femur and it grew back oddly. Yet, it works–this guy was fat and sassy. It would seem amazing that a lizard could break its femur and survive, but here’s the proof.healed broken leg

And check out the tail on this guy. Looks wacky, right?

beat up lizard

The x-ray, however, doesn’t do it justice. It’s not only wickedly bent to the side, but also upwards!

Photo by Manuel Leal

Photo by Manuel Leal

Who knows what we’ll find tomorrow?

Proud of My “Browns”

Me in uniform – many years, kilograms and grey hair ago.

Me in uniform – many years, kilograms and grey hair ago.

For many years, most units in the South African Defense Force used a plain medium brown uniform, called nutria. Soldiers commonly referred to it as “browns.” A few years before my national service, the defense force started phasing it out, replacing it with the “Soldier 2000” camouflage design. When I was conscripted to serve in the South African Medical Services (SAMS) in 1993, SAMS was the only unit that completely still used the nutria uniforms, and although not as “modern-looking” as the other uniforms, we developed a sense of pride in our “browns.”

I believe the brown anole (Anolis sagrei) needs little introduction to Anole Annals readers. I am very fortunate to have been able to do my research on the invasive population of these lizards in southwestern Taiwan. I have been a naturalist at heart since a very young age, but these lizards were my introduction to the academic side of natural history, and because of my work on them I have made numerous friends and acquaintances. So, naturally they hold a special place in my heart and mind.

A female brown anole (Anolis sagrei) from my study area in Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

A female brown anole (Anolis sagrei) from my study area in Santzepu, Sheishan District, Chiayi County, southwestern Taiwan.

Unfortunately these feelings brought a sense of guilt within me. I know all too well that they are an invasive species, which has certain impacts on native species. And yet, it is hard not to marvel at them and their ability to overcome the numerous obstacles they face in this foreign habitat.

The other day, while reading the obituary of Henry S. Fitch (1909-2009) in the 2009 issue of Herpetological Review (40[4]: 393-400), the words of Raymond B. Huey suddenly made it all so clear to me. He described an instance in which he left a meeting at which Henry Fitch was a speaker, with a haunting lesson, “We should do science because we love the process, not because we need to love the results.” I believe that for us who work with invasive species, this is also a message. So now, when I see brown anoles, I no longer have to feel guilty when I do not wish they were rather tree lizards (Japalura spp.) or grass lizards (Takydromus spp.). I admire the “browns” and I find the process of learning about their natural history truly fascinating – I love it! I wonder how many other researchers working on invasive anoles share this sentiment?

Club LizKids – Sign Up Again!

Club LizKids appears to be the new…

Many of you visited my lab’s website for kids – – in the past few days, and a good number of you signed up your children to be a member of our Club LizKids email list.  Thanks so much for your interest!  We hope you and your kids will find this to be a fun group.

BUT, in my recent communication with some of you, I’ve learned that only some of the Club LizKids notifications were coming through to me, even though you received a message confirming your submission.  My web developer (the amazing Tara Whittle) jumped right on that, and we’ve now fixed the problem.  So, if you tried to register for LizKids earlier, please do so again!  

New Green Anole from Colombia

Anolis limon


Anolis limon on top, and the closely related A. chocorum (middle) and A. ibanezi (bottom).

The parade of new anoles continues, and this one is beautiful! Velasco and Hurtado- Gómez, in a new paper in Zootaxa, describe a new species of green anole from northwestern Colombia, Anolis limon. The species is closely related to other green lovelies, but differs in dewlap color and a few other characteristics.

As we have chronicled in these pages, the number of anole species continues to rise, up to 388 according to these authors. More importantly, Colombia—lucky place—is the global leader in anoles, with 75 species.

Here’s the etymology of the name: “The specific name limon makes reference to the resemblance of the body color of the females to the green color of the fruits of the lemon tree (Citrus x lemon).”

And the figure below reveals the distribution of the new species and others.


New Lizard-y Website for Kids

If there are any children in your life that are interested in lizards (and what kids aren’t?!), you may want to check out a website my lab is developing:  This website is one of our outreach efforts to help make connections between schoolchildren (particularly around the fifth-grade age/reading level) and scientists.


We’re working to meet several goals with this website:

1.  To show children how science is done.  Too often, children (and adults) have misconceptions about the process of science.  So, our website aims to show that scientists work together in teams; that scientists use math, communication, and problem-solving skills; that scientists are a diverse group of people; and that science can be a lot of fun.

2. To make science accessible to students.  By writing about our ongoing research projects at the fifth-grade reading level, we hope to engage young children with the idea that they, too, can be scientists. The website also offers several options for website-users to engage with the scientists in my lab, including Club LizKids, an email listserve that connects with kids via more personal updates from the lab.

3. To provide resources for teachers to use lizards in their own classrooms.  Because science is tested for the first time in Texas in the fifth grade, in some cases science is not taught until the fifth grade.  We are working with local (San Antonio) fifth grade teachers to develop resources that help them to teach the Texas science standards using creative, engaging approaches – although the resources on the website are available to all!

We’d welcome your feedback on the site.  We aren’t drawing a lot of “comments” on the blog posts yet, but we do get a lot of hits, so people are finding us.  Hope you enjoy it!

Indian Robin chasing a Sitana

I’ve been re-watching some of my Sitana videos from 2012, and was reminded of an odd interaction between an Indian robin and a male fan-throated lizard (Sitana ponticeriana), from a population in Kutch, Gujarat, in western India. Usually, Indian robins and fan-throated lizards don’t pay much attention to each other. Here’s a video in which a lizard displays when a pair of robins pass by. His dewlap remains extended for a while, which is uncharacteristic, but the interaction doesn’t escalate:

But in the same population, an Indian robin chases after a male fan-throated lizard, after the lizard first ran in the direction of the robin. He starts perched on the rock in the centre of the screen. Here’s a video, slowed down to half-speed. When filming,  I had no idea what was happening, or even where the lizard was, which explains why the camera deviates from the lizard for a while (apologies). 

I’m not sure what’s going on. I didn’t think robins eat lizards–do they? Maybe it thinks the lizard’s tail is a worm? Maybe it’s just playing? Any further ideas?

Spotlight on Cuban Anoles III: Anolis vermiculatus


I don’t think I’ll run into any disagreements by claiming that Anolis vermiculatus is hands-down one of the coolest anoles in existence. First of all, it’s huge – up to 123mm SVL for males. They have blue eyes. They are capable of eating fish and amphibians. They can run across water, and are “truly aquatic” (Schwartz & Henderson 1991). The males in particular seem more like crested water dragons than anoles. A. vermiculatus is sometimes called “lagarto caiman” in Cuba. Although this might bring to mind Dracaena for some, Anolis vermiculatus is quite a different animal. Nevertheless, the name seems appropriate after meeting the creature.

We got our first chance to see A. vermiculatus while staying in Viñales, a lovely, foggy town surrounded by towering limestone mogotes home to Anolis bartschi. We had originally expected to see them only in Soroa, a legendary locality for Anolis in Cuba and a short drive from Viñales. However, we discovered them in abundance along the densely vegetated banks of the mud-brown stream running between our hotel and the road.

A blue eyed male Anolis vermiculatus

A blue eyed Anolis vermiculatus

I generally found A. vermiculatus to be the hardest lizard to get a decent picture of that we encountered (with nods to A. equestris and A. vanidicus). Their preferred habitat is full of shade, and A. vermiculatus is quick to retreat there, often spotting clumsy humans from long distance. If molested further, they leap into the water and apparently remain submerged for some time.


The next day, we were scheduled to have an hour in Soroa, but a bus breakdown allowed us two entire hours. We found more A. vermiculatus, a bit more light, and much clearer water, but the lizards remained a wary bunch. Below are females and a juvenile rafting in what looks like a coconut husk. Sexual dimorphism in this species is significant for size (123mm max SVL for males, 83mm for females, Schwartz & Henderson 1991), and coloration.




I did get the chance to photograph two large males. This individual appears to have some sort of parasite (notice the swelling on the side of the neck). Anyone have any ideas what it could be? My guess would be a nematode. I’m unsure if the deformity of the jaw is another of these parasites or perhaps a different injury.


Although A. vermiculatus is able to run across the surface of water, we did not observe this behavior in our short time with the species. However, it was quite surprising to learn that these lizards do this without the assistance of toe fringes as in Basiliscus.

Here’s the best shot of the bunch:


Next up: a blue lizard that wears yellow pants!

New Film on Snake Research: Do the Lizard Cameos Steal the Show?

A new movie on snake research, an Alex Pyron production, features not only great snake footage, but cameo appearances by anoles and Frank Burbrink explaining how he got out of prison and into herpetology (see disclaimer below), as well as wildfires in the Brazilian Cerrado, and plenty of other frogs, lizards, and rock and roll music.

Alex explains: “Most people think of science as being fairly boring most of the time. They are probably right. However, readers of this page are more likely familiar with another side of the story. Those of us who do field work are lucky enough to get paid to flip rocks for a living, chasing after the most exciting creatures on the planet. Books like Snakes and Snake Hunting and The Snake Charmer captured some of this adventure, and gave many of us an early glimpse into the future careers that awaited us. Bringing this magic to the silver screen is snakehandlers: these signs shall follow them, the new documentary about field herpetology that you never knew you needed (or wanted).

Shot across one year, snakehandlers follows Alex Pyron and a rotating band of pirate misfits across the U.S., Panama, Ecuador, and Brazil in search of tissue samples from the rarest (and commonest) herps around, to fuel the fires of our phylogenetic frenzy. Along the way, a wildfire rips across the Brazilian Cerrado, the clouds boil in the Northern Andes, Frank Burbrink shares his hard-luck tale of crime and punishment on the road to redemption from state prison to evolutionary biology*, famous herpetologists from the past speak to us across time, and new species are discovered left and right.

At its core, snakehandlers tries to answer the question of why we work with snakes to begin with. Herpetologists from every corner share their stories about the interests and experiences that brought them into the field. On the whole, though, the question remains unanswered; how could it be? Why do we do something as crazy and absurd as handle snakes or chase anoles? Watch snakehandlers and see if you can figure that out for yourself, in a movie that does for snakes what Plan 9 did for Outer Space.

As a plus (or a main attraction) for readers of Anole Annals, have fun spotting at least six species of Anolis from North, Central, and South America! Happy herping…

*The producers of snakehandlers were unable to verify the accuracy of all participant interviews.”

Fluorescent Lizard Skeletons Used to Precisely Measure Growth

Several weeks ago, Anole Annals highlighted a recent paper that uncovered the molecular bases of craniofacial dimorphism in the carolinensis clade of Anolis lizards (for full disclosure, I am the lead author of that paper). Hidden deep within that research is a relatively new technique for precisely measuring rates of skeletal growth that may be of interest to the community. I briefly introduced this technique several years ago in a post about methods of skeletal preparation, but with the details of this method now available it is worth highlighting once more.

Double labeled facial skeleton of A. carolinensis. Green label (calcein) and red label (alizarin complexone) separated by 30 days.

Because some images shouldn’t be lost in the supplementary materials. Double labeled facial skeleton of A. carolinensis. Green label (calcein) and red label (alizarin complexone) separated by 30 days.

Growth in body size can often be measured using calipers or a ruler. But in some situations a finer-scale analysis may be necessary, such as when differences in growth rate may be subtle, within the range of error associated with those manual methods. Fluorescent calcium chelators provide the precision needed to measure differences on the order of microns per day. In the recent paper, this technique was used to measure facial elongation in sexually mature green anoles, which was only ~8um per day in males and ~4um per day in females. These compounds are stable, are not highly toxic to animals, are relatively inexpensive, and can be easily used in the field or the lab. They can also be applied to adults or hatchlings with little modification to the protocol as injection volumes are typically 10-20ul depending on size. Ultimately, there is a lot of versatility to the way in which this method can be applied.

Dimorphism in facial growth rates between male and female A. carolinensis. Modified from Sanger et al. 2014.

Dimorphism in facial growth rates between male and female A. carolinensis. Modified from Sanger et al. 2014.

While new to herpetology, this technique was adopted from the biomedical literature on fracture repair where precise spatiotemporal measure of bone deposition is required. The general experimental framework is that pulses of chelators with different fluorescent properties are delivered at distinct intervals, the skeleton prepared, and the distance between the labels recorded from digital photographs. Calcium chelators are available that fluoresce under many of the standard filters used in modern microscopy – including green (calcein), red (alizarin complexone), orange (xylenol orange), and blue (calcein blue and oxytetracycline) – offering great experimental flexibility. Once incorporated into the bone, their signature remains strong for at least 30-45 days, until it is remodeled away as the living skeleton continues to grow and reshape itself. In the recent paper on craniofacial dimorphism, fluorescence in the facial skeleton could be observed following simple removal of the skin because the face has little to no overlying connective tissue. Measuring growth of the vertebrae or limbs is also possible, but may require careful sectioning of the bone using either plastic or paraffin protocols. Ultimately I think that there is a lot of potential with this method that has yet to be explored in the context of organismal biology. I hope that by highlighting this method here more people become aware of its utility and give it a try.

Whose Tail Crest Is That?

Which species owns this lovely tail crest?

Which species owns this lovely tail crest?

Some anoles sport fancy dorsal tail crests. It would be interesting to survey the distribution of tail crests–they are only found in some areas, and species of some sizes and not others, and those in particular microhabitats. Quick–can you think of a mainland anole with a tail crest?

But I’m guessing the species above is not one that comes to mind when you think of tail-crest bearing species. Whose is it? The answer’s below the fold.

Continue reading Whose Tail Crest Is That?

Draco Shares the Anole Limb Length–Perch Size Relationship

A recent study in Oecologica by Terry Ord and myself found striking parallels in habitat use and morphology between the phylogenetically distinct Anolis and Draco genera.  Draco (family: Agamidae), for those who don’t know, is a genus of gliding lizards found throughout southeast Asia that are similar to anoles in that they communicate with conspecifics using bright and diversely coloured dewlaps (see picture).

IMG_2234  anole

(L: Draco sumatranus; R: anole)

A defining characteristics of anole ecology is their ecomorphology – a description of the species microhabitat and its morphological adaptions for thriving there. Anole species living sympatrically avoid interspecific competition by partitioning their habitats and resources, and consequently develop morphological adaptations that are suited to their slice of the habitat. As Draco species are also often found in sympatry, we tested whether competition pressures had resulted in similar habitat partitioning and corresponding morphological characters (or ecomorphs). Whilst it’s perhaps a bit early to suggest that Draco have  evolved the full complement of anole ecomorph classes, the Draco taxa studied largely clustered into two groups that shared characteristics with the Greater Antillean anoles. The figure below (panel b) shows a combined Draco/anole phenogram, based on morphology and ecobehaviour (the anoles are labelled only by ecomorph). The Draco species fall out largely in line with groups of ‘trunk-ground’ anoles towards the top of the phenogram, and ‘trunk-crown’ anole towards the bottom. Phenogram ecomorph

One of the better diagnostic features of the Greater Antillean anole ecomorphs are the differences in perch use and subsequent differences in limb length. The plot below shows total hindlimb length (size-free residuals) of adult males of Draco species and Greater Antillean anoles, as a function of perch circumference.  The relationship between limb length and perch size is nearly identical between the groups, with a very similar slope, and only a difference in y-intercept owing to differences in body length (Draco bodies are elongated to accommodate gliding membranes).  The same unit increase in perch size results in the same unit increase in limb length for both genera.

These results are surprising considering that this relationship has not been found in species that are more closely related to the Greater Antillean Anolis (see study for references) and because Draco and Anolis have very different ‘key innovations’ for locomotion in their respective habitats (toe pads for Anolis and gliding membranes for Draco). This implies that Draco species have experienced interspecific competition over resources in similar ways to the anoles, resulting in homologous character displacement. 

Evolutionary History of the Green Anole in the United States

tollis1It’s an old story: a Cuban émigré arrives in Florida, thrives and then sends out roots, in the process becoming completely Americanized. I refer, of course, to the green anole, Anolis carolinensis, derived from grand-daddy porcatus in Cuba. But the exact story of carolinensis‘s spread–when, by what routes, where–is still unclear. Two years ago, a pair of papers reported interpretations based on sequences of mitochondrial DNA, revealing a somewhat complicated history of green anole diaspora. Now, in a recent paper in Genetica, Tollis and Boissinot revisit this question, bringing to bear the power of a multi-locus, nuclear gene sequencing effort. Their results lead to a simpler, more satisfying story, and suggest that we need to be wary of placing too much faith in phylogeographic/evolutionary scenarios derived from mitochondrial DNA.

Here’s the tail end of their abstract:

“We find that all demographic events occurred during or after the Upper Pliocene and suggest that green anole diversification was driven by population divergence on interglacial island refugia in Florida during the Lower Pleistocene, while the region was often separated from continental North America. When Florida reconnected to the mainland, two separate dispersal events led to the expansion of green anole populations across the Atlantic Seaboard and Gulf Coastal Plain.”

Their inferred evolutionary relationships are portrayed above, and their biogeographic scenario below.



Does the Gender of an Observer Affect Lizard Behavior?

Hard at work studying lizards (from a previous AA post on best practices in lizard videotaping in the field)

The New York Times reported today on a recent paper in Nature Methods that indicated that stress levels of lab rats varied depending on whether the scientist in the room with them was a man or a woman. This effect existed even in response to t-shirts worn by a man or a woman.

This got me thinking: could the same factor effect lizard behavior studies? In many cases, anoles are studied by an observer quietly watching or recording lizards from a distance of a few meters. Many anole species seem unperturbed by the presence of observers and go about their activities in a seemingly natural way. But does the presence of an observer have an effect? Are they warier? Do they display less? And, more to the point, does the identity of the observer have an effect? Men are, on average, bigger than women, so might that matter? Some people are more fidgetty than others. Clothes? Facial hair? I am aware of a few studies on observer effects on lizard behavior (such as this one on the brown anole), but not many.


Anolis carolinensis in Alabama–What Do Green Anoles Do When Browns Aren’t Around?

carolinensis on pine alabamax

Something you don’t see every day: a green anole on a pine tree.

Through the years here at AA, we’ve had discussion of the habitat use of the common green anole. In particular, there is a persistent belief that before the brown anole emigrated from Cuba, green anoles used all manner of anole habitat, from the bottom of trees to the very top of the canopy. Once the browns arrived, however, greens seem to have repeated back up the tree, ceding the low perches to the browns.

This is a very nice story, and probably true, but it’s surprising how little documentation we have of the habitat use of green anoles in places where browns don’t occur. In fact, more generally, it is quite surprising just how little we know about the natural history of green anoles throughout their natural range. For such a common species, you’d think its biology would be extremely well-known, but that is far from the case.

A while back, Janson Jones referred to the green anoles in his then-neighborhood (he’s since moved) in Georgia as low-riders, a possible example of green anole habitat use in the absence of browns. With this in mind, I was delighted to get a chance to see what the greens are up to in Alabama, a state that is still mostly–at least for now–mostly brown anole free.

Across the street from Pi Kappa Kappa.

Across the street from Pi Kappa Kappa.

On the campus of the University of Alabam in Tuscaloosa, greens were moderately abundant when the sun was out. The fellow to the right was strutting his stuff on sorority row, but his comrades elsewhere were in similar habitats on trees, moving up to into the canopy when harassed by an old dude with an iPhone.

But then I had the good fortune to get taken to a nearby pine forest by whiptail lizard geneticist turned turtle biologist Peter Scott, a grad student at UA. Peter told me that he often saw (or, rather, heard) green anoles scurrying through the leaf litter when he approached, running to the nearest tree which it then ascended. It seemed unlikely, but sure enough, that’s where the greens we found were, down low, in very un-green anole-like habitat.

carolinensis in the litter Alabama

Alabama low-ridin’ green anole

Of course, these were just a few observations made over the course of a short hike one afternoon. But clearly there’s a lot to learn about green anoles–what they do in places without competitors, and how that changes when brown anoles arrive. Seems like a great project out there, just waiting for someone to do it.


Rampaging Wrens Chow Down on Green Anoles

Wrens seem like such harmless, friendly little birds. And with such a dainty little beak, how much damage could they do? Imagine our surprise, then, to learn that they may be voracious predators on our beloved anoles. Thanks to the observations of Roger Birkhead and Mark Benny, reported in the most recent issue of Herpetological Review, we now know the true nature of these little beasts. Here’s what they saw (Herpetological Review 45(1):123-124, 2014):

wren“On 14 August 2013 around 0730 h MCB was observing the birdfeeders and birdhouses at his residence (Harrison Co., Mississippi, USA; 30.387325°N, 89.021624°W, datum WGS84/NAD83) when he noticed a commotion near the potted plants on his front porch. An adult Carolina Wren (Thryothorus ludovicianus) was observed smacking and shaking something large and elongated. When the wren flew up to the nearby birdhouse it became apparent that it had a juvenile Anolis carolinenis in its beak which it quickly fed to its chicks. This behavior was observed for a second time at approximately 1130 h. A third anole was observed being fed to the chicks at 1619 h (Fig. 1). There were at least two exchanges of food missed while leaving the point of observation to retrieve and set up a camera, but were evidenced by long green tails protruding from the entrance hole of the birdhouse that were longer than the lizard in Fig. 1. Adult wrens were also seen bringing larger unidentifiable pieces of flesh assumed be the remains of a larger dismembered A. carolinensis. Similar behavior has been noted for vireos feeding on A. carolinenis (Sykes et al. 2007. Wilson J. Ornithol. 119:508–510). Additional observations were made on 15 August and 16 August of both whole lizards and parts being brought in by the adult wrens. Lizards are identified in the diet of the Carolina Wren as far back as 1916 (Beal et al. 1916. Common Birds of the Southeastern United States in Relation to Agriculture. Farmers Bulletin 755, 40 pp.), but no species identifications were provided. Generally, predation of vertebrates by passerine birds is considered uncommon (Lopes et al. 2005. Lundiana 6:57–66). This observation is the first documented record of A. carolinensis being consumed by Carolina Wrens and judging by the frequency of captures noted here this wren species may be a significant predator of anoles at least during the bird’s nesting season.”