Tag Archives: bahamas

Notes from the Field: Predation on Anolis sagrei on Isolated Cays in Abaco, Bahamas

Curly tail with brown anole tail visible from its mouth

Curly tail with brown anole tail visible from its mouth

Kayaking to the cays

Kayaking to cays

I was recently in Abaco, Bahamas with Losos lab post-doc Oriol LaPiedra and Ph.D. candidate Darío Fernández-Bellon from University College Cork, Ireland, to carry out some behavioral studies of Anolis sagrei on the island and its surrounding small cays. We kayaked (a highly recommended transportation mean for its lesser-impact on the marine ecosystem, not having to rely on the tide schedule, while allowing you to see rays and sharks and sea turtles!) our way out to islands that are known to have A. sagrei naturally existing alone, or with one of their natural predators, Leiocephalus carinatus.

Curly-tailed lizards are known to prey on A. sagrei and can have significant impact on anole behavior and adaptation. Twice I observed Leiocephalus capturing and consuming A. sagrei, one of which was an adult male and the other an adult female. We have also noticed that the A. sagrei on these island tend to perch higher and are seldomly seen on rocks or leveled ground compared to those on islands without curly tails, so this behavior could be an effect of Leiocephalus being present.

A female red-winged blackbird with a brown anole in its beak

A female red-winged blackbird with a A. sagrei in its beak

On a different island where Leiocephalus were absent, A. sagrei are still under predation pressure, this time by red-winged blackbirds nesting on the island. We observed a female blackbird with an A. sagrei in its beak waiting for us to leave the island so that it can feed its chicks. This observation suggests that A. sagrei on islands without Leiocephalus might still be under predation pressure by other species that might not be present on the island at all times. Also, predation pressure exerted by an aerial predator differs from that by a terrestrial predator or if both predators are present, so this might be a factor in morphological or behavioral changes in these lizards on these islands.

Anolis sagrei on one of the small cays

Other interesting observations include A. sagrei density on islands seems to be unintuitive. Some small islands with fewer perches hosted many more adult males and females than large islands did. Sizes of individuals also seem to vary greatly between different islands: small cay A. sagrei seem to be, on average, larger than those on mainland Abaco. Personally, I am unable to note major differences between islands which might have resulted in these observations. I’m excited to see if the data we’ve collected will give more insight into these observations as well as other behavioral results that will come from this study!

Notes from the Field: Another Successful Bahamian Adventure

AbacoI just got back from a trip to the Bahamas with Losos lab post-docs Anthony Geneva and Alexis Harrison, accompanied by expert lizard catchers Inbar Maayan and Sofia Prado-Irwin (Harvard graduate student). We parted ways for the first few days of the quick trip, with Anthony and Sofia headed to Bimini and Alexis, Inbar, and myself on Abaco. Read more about the Bimini trip in Sofia’s recent post.

Deck at the Friends for the Environment Kenyon Center field station

Friends for the Environment Kenyon Center field station

On Abaco, we stayed at the brand new Friends of the Environment Kenyon Center. We were really impressed by the great accommodations of this field station. The station was sustainably built and had all the modern amenities we could wish for. The field lab was large and equipped with microscopes and plenty of counter space. We were equally impressed by the staff and their outreach efforts. The Friends for the Environment does a fantastic job providing nature education to local kids from age 3 through college! Their ambitious organization seeks to provide high-quality and low-cost facilities for visiting scientists and to provide outreach and education to the local community. We spoke with the coordinators of the organization who told us that any time researchers are looking for extra hands in the field they are happy to arrange local students to assist. We strongly encourage others traveling to Abaco to stay here!

In the end we will conserve only what we love, we will love only what we understand, and we will understand only what we are taught.” – Baba Dioum (posted at the Friends for the Environment)

Our main goal on this trip was to capture Anolis sagrei to continue ongoing research into the amazing diversity among islands in this species. We were immediately struck by how much smaller the Anolis sagrei on Abaco were compared to those on the other islands we have been to. I was also struck by how many A. sagrei used the ground. I normally study Anolis cristatellus, and although they are the same ecomorph, I rarely see A. cristatellus on the ground. I also don’t recall seeing A. sagrei frequently on the ground on Bimini or Eleuthera. So observing these lizards, particularly the females, on the ground at such a high frequency (they literally scattered as I walked!) was very surprising. Is this common on other islands with A. sagrei and I just haven’t noticed before?

As with any good field trip, we also encountered a great diversity of herps. Although the only native anole to Abaco is  A. sagrei (according to Powell and Henderson 2012), we also saw plenty of Anolis distichus and a few Anolis smaragdinus. We also saw the invasive Cuban tree frog (Osteopilus septentrionalis), the native Eleutherodactylus planirostris, and plenty of curly-tails (Leiocephalus carinatus). No live snakes to report, although we did come across a couple of roadkill Cubophis.

Although we found no Sphaerodactylus, we did find plenty of non-native Hemidactylus. Interestingly, Hemidactylus is not listed in Powell and Henderson’s (2012) list of West Indian amphibians and reptiles for Abaco. Can anyone ID this species (the photos are of two individuals) and tell me if this has been reported before for Abaco? Obviously Hemidactylus are widespread in the Caribbean, but I was surprised to see it absent from the species list for many of the Bahamas islands.

Continue reading Notes from the Field: Another Successful Bahamian Adventure

Anolis sagrei Survey Continued: Eleuthera, The Bahamas

beach scrub and bay scenic 2

I just got back from a short trip down to Eleuthera in The Bahamas where I was assisting Anthony Geneva (Harvard post-doc) in sampling lizards. Also along for the trip were Sofia Prado-Irwin (Harvard Ph.D. student) and Rich Glor (University of Kansas). We went with the main goal of sampling Anolis sagrei from four habitat types found commonly in the Bahamas as an extension of an ongoing project in the Losos lab (previous posts from: Rum CayConcepcion IslandRagged IslandBiminiMangrove habitat, and Great Isaac Cay). Specifically, we were looking to sample Anolis sagrei in mangrove, secondary coppice forest, closed coppice forest, and beach scrub habitats. These habitats differ in the height of the canopy, density of the understory, and composition of plants.

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We focused entirely on the southern half of the island near Rock Sound and Cape Eleuthera. We were successful in sampling two beach scrub habitats, two mature coppice forest, one secondary coppice forest, and one mangrove habitat. We were able to catch all four of the anole species found on Eleuthera: Anolis angusticeps, Anolis distichus, Anolis sagrei, and Anolis smaragdinus. We also encountered a number of other native herp species: the Bahamian boa (Chilobothrus striatus), Ameiva auberi, Eleutherodactylus rogersi, curly tailed lizards (Leiocephalus carinatus), and the Bahamian racer (Alsophis voodoo), as well as a couple of non-native species: Cuban tree frog (Osteopilus septentrionalis), and Hemidactylus mabouia.

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In my own research I work with Anolis cristatellus, the Puerto Rican crested anole. I am always surprised when I catch A. sagrei by how much smaller they are than A. cristatellus, although very similar in appearance otherwise. On this trip, I was also surprised that the A. sagrei, as well as the A. angusticeps and the A. smaragdinus, appeared to be much smaller than those I had encountered on Bimini last spring.

We also found that the density of lizards was quite low compared to what we expected and what I had experienced in Bimini, both during the day and at night. In all four of the habitat types, we saw an abundance of hatchlings, juveniles, females, and small males, but relatively few full adult male A. sagrei. For A. angusticeps and A. smaragdinus, we encountered only a few individuals total during the week of sampling. This reminded me of an odd experience I had last fall in Puerto Rico with A. cristatellus. It was the same time of year and I had an extremely difficult time locating mature animals in sites where I had previously sampled large numbers during the spring and summer months. Instead, I observed a large number of very young animals and females. I’m curious if this is a coincidence or if perhaps there is a strong seasonal effect on either male behavior (i.e., reduced visibility outside of the mating season) or male abundance (i.e., reduced numbers because of mortality during the mating season). In other words, are the males still there, but hiding, or are they really lower in abundance in the late fall? Or maybe I was coincidentally unlucky on both trips… I am very curious to hear thoughts on this!

Anolis sagrei using coral ground habitat.

Anolis sagrei using coral ground habitat.

Finally, I want to end with a short natural history note on the habitat use of the A. sagrei in the mangrove habitat. In this habitat we observed A. sagrei using perches at drastically different heights: some were 6 feet up, others were on the ground. Interestingly, the ones on the ground did not appear to be in transit, but seemed to be using the pockmarked karst as perches, running into one of the many holes when approached. Has any one else observed this behavior before? It seems so different from the typical trunk-ground anole perch and behavior to me.

That’s all for now. Currently Anthony is sampling additional islands in the Bahamas along with Melissa Kemp (Harvard post-doc) and Colin Donihue (Yale Ph.D. candidate / Harvard visiting student). Best of luck to them, I can’t wait to hear how the rest of the trip went!

Species ID from Bimini – A. sagrei or distichus?

After looking through my photos from my trip last week to Bimini in the Bahamas, I was disappointed when I realized that none of us seemed to have any pictures of Anolis distichus. Or maybe we did? Among all the typical sagrei-looking anole photos was this guy:

Anolis distichus or Anolis sagrei???

Anolis distichus or Anolis sagrei???

Without telling you why I thought this was a distichus, or why others I have asked are torn between distichus and sagrei, I am curious what people think. What species is this?

Field Trip Recap: Herps of Bimini, The Bahamas

 

Searching for Anolis sagrei on the beautiful island of Bimini

Anolis sagrei on the beautiful island of Bimini

I just got back from a 10 day research trip to Bimini in the western Bahamas along with Harvard post-doc, Graham Reynolds, Harvard graduate student, Pavitra Muralidhar, and UMass Boston undergraduate, Jason Fredette. We went with the simple goals of kicking off a research project in the Losos lab on Anolis sagrei  and to observe as many other herps as we could.

We spent the majority of our time on South Bimini. We sampled from the well-maintained Nature Trail, where we found all four anole species (Anolis sagreiAnolis smaragdinusAnolis angusticeps, and Anolis distichus) and a Bimini boa among diverse habitat types, including blackland coppice and open Coccothrinax shrub. We also spent a couple of nights searching in some mangrove forest near the airport, which yielded only A. sagrei and A. angusticeps and in low abundance at that. The “Fountain of Youth” ended up being a gold mine for Sphaerodactylus nigropunctatus as well as boas — we caught 3 here.

We also did a fair amount of exploring. Our hosts for our house rental wanted to make sure we had a great time in Bimini and so they insisted on boating us out to a couple of the nearby islands for some snorkeling. Of course, we saw this as the perfect opportunity to catch a few lizards. Our first destination was Gun Cay, a small island a few miles to the south of Bimini. Pavitra and Jason entertained our hosts by collecting shells and feeding stingrays. Meanwhile, despite our hosts’ curiosity that we wanted to go wander in the brush, Graham and I nabbed 10 adult male A. sagrei in less than an hour. We also saw several Ameiva auberiAnolis smaragdinus, and some sort of very large rodent (does anyone know about Hutia reintroductions in the Bahamas?).

The following day, our hosts insisted we come with them to a small island 20+ miles to the north of Bimini (Great Isaac Cay) where they promised us dolphins and hammerhead sharks. On the way to the island we saw several dolphins, tons of flying fish, sea turtles, and several large nurse sharks. As we approached the island, I saw the mature Casuarina forest and yelled down to Graham from the crow’s nest tower, “I want to go explore there!”  Our hosts got us as close as they could to the rocky shore (dangerously close it seemed, the hull almost hit the rocky karst island) and all four of us hopped onto the island. The island had an abandoned lighthouse and buildings from the 1800’s that we explored. We were shocked to not find a single anole on Isaac Island, although we did find Sphaerodactylus nigropunctatus and Ameiva auberi.

The isolated Great Isaac Cay with ruins from the late 1800's.

The isolated Great Isaac Cay with ruins from the late 1800’s.

The trip was a huge success. In total, we came across all but five of the reptiles of Bimini. Surprisingly, we were unable to find any Bahamian racers (Alsophis vudii) other than roadkills, though most of our field time was at night. Unsurprisingly, we did not find either of the blind snakes or the dwarf boa, the latter of which tends to be more common in the rainy season. As expected, A. sagrei was the most abundant anole on Bimini. We came across A. angusticeps and A. smaragdinus with equal frequency and actually encountered only a few A. distichus. We did most of our searching at night, so this may be a reflection on different sleeping behaviors rather than abundance.

In summary, we were able to observe:

  • 140+ Anolis sagrei males and females
  • Sphaerodactylus nigropunctatus (black-dotted dwarf gecko)
  • Sphaerodactylus argus (ocellated dwarf gecko)
  • Dozens of Leiocephalus carinatus (curly-tail lizard)
  • Chilabothrus strigilatus fosteri (Bimini boa)
  • a handful of Anolis distichusAnolis smaragdinusAnolis angusticeps

We also saw a number of other herps that we were not able to catch or didn’t need data from:

  • Ameiva auberi (Bimini ameiva)
  • Eleutherodactylus planirostris (greenhouse frog)
  • Osteopilus septentrionalis (Cuban tree frog)
  • Hemidactylus mabouia (invasive house gecko)

 

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Bahamas Research Update: The Impending Armageddon

AA readers may recall a series of post this past May, in which I discussed research on anole ecology and evolution in the Bahamas. Those posts discussed studies that have been ongoing in Abaco for several years on the effect of predators (curly-tail lizards) on anoles, as well as studies initiated this year to the south in Staniel Cay.

Hurricane Irene, predicted to reach Category IV status, is now bearing down on the Bahamas from the south. And if you examine the hurricane’s track, you’ll see that she is aiming right at our study sites. What will happen? In the past 13 years, we’ve had three experiments terminated by hurricanes. Please cross your fingers, toes, and any other extremities in hopes that fourth time is a charm.