A new method for taking toepad pictures in the field!

This is a reblog of a post I wrote over on Anole Annals

IMG_5619

Getting good pictures of lizard toepads in the field can be tricky. Flatbed scanners are heavy and don’t take well to transit bumps and bruises, and getting a digital camera to focus on the toe, not the glass, requires surgical precision on the manual focus ring. I’ve just found a new solution for an iPhone (or GooglePixel, if that’s how you roll), and I’m eager to share.

Continue reading

Drones to data

I’ve posted a lot of really pretty drone pictures and video these last six months and I’m realizing that this drone is actually pretty exciting tool for science communication. A reporter the other day said that she’d watched my Redonda video as part of her background research and it really helped her get a feel for the island. The original intent for the drone though was to capture high-resolution aerial photos of study sites to try to capture data on important but hard to measure ecological characteristics like vegetation cover, habitat availability, and maybe even habitat structure.

It’s a rainy Saturday in Boston so I decided to go back and look at some pictures from sunny Greece and see if I could start working with the drone footage to get some data.

The first step is actually capturing the video, of course, and that happened in Greece. I flew at a constant height (40m) in a straight line along the long axis of the island with the drone camera pointing 90 degrees straight down.

Here’s what that video looks like (don’t forget to click HD):

Now, that’s really pretty but for analyses I want a single, static image of the whole island. One option would be to just fly really high so the entire island is in the field of view. Unfortunately, since this island is so long, that’d have put me way higher than I wanted (or was allowed) to fly. This would also cause the resolution to suffer – I want to be able to see individual plants pretty clearly. The other option is to decompose that video, frame by frame, into a series of still images that I can then stitch together into a panorama.

This is actually pretty straight forward in in photoshop:

File > Import > Video Frames to Layers…

In this dialog box you select the video you want to make into still images and how many frames you want to skip per layer (the default is one layer every 2 frames). I chose one layer per 30 frames or approximately 1 image per second of video. That’ll give me good overlap to stitch the panorama together but not so many images that my poor computer will have to jigsaw hundreds of pictures together. You can then save those layers as independent images.

The final step then is just stitching together the panorama! Again in photoshop:

File > Automate > Photomerge…

Default settings worked great for me and voila, a beautiful high-resolution aerial photograph of an island in Greece.

Agios Artemios

Click on the image for a high-res look at Agios Artemios

So what about the data? I used my Oru Kayak seat as a launching pad on each of these islands. You can see it as the bright orange oval in the bottom third of the island. That orange launch pad is 80 cm across. With that I can set a scale that’s consistent for the whole island. I also know that the kayak is 360 cm long, which means I can check my calibration to make sure I’m getting good estimates. After that, it’s time to measure. I’m running out of time today so I haven’t made measurements but I’ll be calculating the  area of the island, the area of the green space, maybe even some metrics of patchiness, stay tuned!

An update on the Italian Wall Lizards in Boston

After being gone for all of May I was very eager to get out to the Fenway Victory Gardens to see how the Italian Wall Lizards were doing. We discovered the population last year but this far north we were really not sure whether they’d make it through the winter. Just before the Bahamas trip reports started coming in that at least a few had been seen around the gardens but I never got the chance to get down there to see them myself. What’s more,  I’d offered to give a workshop to the Fenway Garden Society to tell gardeners (and anyone else interested) a bit more about the lizards. I was nervous as the date for the workshop approached about whether we’d see any lizards to use for show and tell.

IMG_3586

Lizards in the gardens! A flier for my talk. (Photo credit to Claire)

A few days before the workshop and just after I returned from Greece, Claire and I walked through the victory gardens. We didn’t find a single lizard. Oh oh. Two friends and I went to the garden the next day to look to see if we could find anybody. We got a good look at a female and a male (whew!) but they escaped into a dense tangle of compost. Alright, so there are lizards but I really wanted to catch one for show and tell during the talk. So, I went searching again the next day and hurrah, I caught a nice male to show people!

IMG_5216

Here I am gesturing at a rock in a cage. I promise the lizard was in there somewhere. Also, evidently I gesture a lot when talking. (photo credits to Claire)

The lizard workshop went really well. Just over 30 people came and asked great questions.

IMG_3567

There! Now you can see the lizard.

Here are a few of the questions that came up:

  • Where did they come from?
    • Well, ultimately these lizards are natively found through much of the Italian peninsula though they’ve been good colonists throughout Europe and parts of North America. Preliminary DNA analysis suggests that the Boston populations are closely related to the Connecticut and New York populations (more on this as soon as we firm up the analyses), which suggests that the Boston populations were taken from NY or CT and brought here.
  • What do they eat?
    • These lizards are insectivorous meaning they’ll be chomping down on the loads and loads of bugs crawling around the gardens. Some of those bugs are pests – excellent – some are pollinators – alas – they’re pretty indiscriminate eaters. Some populations of the lizard have been found to eat plant material but that’s usually only when they’re living on pretty desolate islands where they can’t get enough insects. I suspect this population isn’t going to be going vegetarian while there are so many delicious beetle larvae and caterpillars to be found.
  • How many of them are there?
    • Last year we saw about two dozen but there was evidently a pretty significant die-off over the winter. So far this spring I think I’ve seen a grand total of seven (never all on the same day) scattered around and I’d guess for every one I see there’s another one or two that is too well hidden to find. That’d put the population in the gardens right around 15.
  • How do they survive the winter?
    • Boston locals will know our winter’s aren’t a joke; it can get wicked cold! This is the northernmost population of Italian Wall Lizard that’s been seen anywhere so they must have found some way to escape the snow. My best guess is that the lizards are over-wintering in the big compost piles around the garden, which can stay warm all the way through the winter.
  • Do they have any predators here?
    • Yes and no, so perhaps a strong maybe. Snakes will certainly eat lizards but I’ve only heard of one garter snake in the gardens so I don’t think that’s going to be a major predator. There are lots of birds of prey that frequent the gardens but compared to the dozens of rabbits dozily chewing on vegetables these lizards are a lot of work to catch and what with the fences all over the place not a lot of birds would risk a dive into the thick of the plots. Cats are the biggest likely predator of the lizards but I haven’t seen any in the gardens.
  • Are they a problem?
    • I’d say no. Right now the population is pretty small and it doesn’t seem like there’s much of a chance of it expanding dramatically given the high-density housing all around the gardens. The Emerald Necklace is right around the corner and could provide great habitat but may not offer the same winter hide-outs as the garden does. More importantly, they aren’t extirpating any other lizard species (there aren’t any confirmed in Massachusetts) and they won’t be dramatically impacting local insect populations at this population density, so I’d say, all in all, we shouldn’t worry about the Italian Wall Lizard becoming a noxious neighbor.
  • Can you move one to my plot? Please?
    • No. The lizards may be ecologically benign, and yes, they’re inordinately cute, but moving species around is a serious no-no. If you want to make your garden plot better habitat for the lizards give them rocks to perch on with good sunlight and scamper under when people approach. If they come, enjoy their company and send me a picture!
  • Have you managed to get the Red Sox to adopt them as a Green Monster mascot?
    • Not yet… but if you know someone please let me know!

IMG_5200

Back from Greece!

Greece came and went this year faster than it ever has before. I think it had to do with the fact that it was the third of my field expeditions this spring. Maybe it had something to do with the only three days at home between returning from the Bahamas and leaving for Athens. Much of my time in Greece was spent breathless trying to get from island to island and now, in retrospect, the three weeks of fieldwork seem like a bit of a hazy dream.

Luckily I’ve got a big stack of data sheets to remember the lizards by.

The goal this year was to revisit the island introduction experiment I started in 2014. This is year three and the first year where all of the lizards we originally introduced to the island have likely died of old age. This means that most of the lizards we were catching were the grandkids of the original colonists and had never experienced any environment other than the little islands they were born on. This is terrific for our ability to start asking questions about evolution over the course of those three generations.

We revisited all five experimental islands and all of the lizard populations are still doing great!

Two of the islands now have well over 100 lizards on them. That’s starting from a seed population of just 20! The lizards are getting big too. It seems like they’re not having any trouble finding food on these little islands.

I’m putting together video from the trip now. I promise to show a bit more restraint in the aerial video than I did on Redonda. Here’s a short fly-over of one of the islands just to give you a look. (Don’t forget to play it on HD). This island was one of our most densely populated – well over 100 lizards on it!

For those of you with a particularly keen eye (and a very long memory on this blog) this is Galiatsos which used to have a fort on it. Here’s a map of the Bay of Naoussa from 1776. Galiatsos is the island with a “Batterie de 35 Canons.”

Big Map

From the flyby you can still see the raised embankments around Galiatsos that formed the foundations of that fort. Once upon a time, those canons were watching over one of the best-protected bays in the Cyclades. It’s fun to be on the island 250 years later and still be able to make out hints of its long history.

 

Frog Party

DCIM100GOPRO

I’m back from the Bahamas but leaving for Greece tomorrow afternoon! Whew. I knew it was going to be a fast turnaround but my head’s spinning trying to keep track of the simultaneous fieldwork wrap-up and start-up to-do lists. I have a couple of pictures and videos ready to share from the Bahamas though so I want to get them posted quick before the next adventure is in full swing.

All in all the Bahamas visit was a success. We shipped 360 lizards back to Harvard for a big breeding experiment and got more data on habitat use for well over 1200 lizards across Eleuthera, Long, and Bimini islands. The team was terrific, the lizards were plentiful, and the weather was perfect. Well, almost.

The final day of fieldwork was a complete washout. As Raphaël said, “C’est la fête à la grenouille” – a party for frogs. Alas, we were after lizards, not frogs, so we stayed in until the last minute hoping it might clear. When it became obvious that a thorough drenching was inevitable though, Raphaël and I put on our swimsuits and set out. We needed to return all of the lizards that we’d caught that we weren’t bringing back to Harvard with us. It was a sloppy wet hour and a half for us but I’m pretty sure the lizards appreciated being brought back home.

Here’s a short video documenting the adventure:

 

A quick picture update from the Bahamas

There’s lots going on here in the field. We’ve just wrapped up collecting on Eleuthera and Long Island. I’m back on New Providence swapping out crew. Rob left after Eleuthera. He swapped spots with Geoff. We just lost Jon – a champion lizard catcher on Eleuthera and Long. Raphaël is still here and we’re being joined by Angus and Pavitra tomorrow. The rapidly switching roster is actually the least of the logistics worries but today, with twenty-dozen lizards safely ensconced in a cooler on their way back to Boston, I’m finally taking a few deep breaths.

Here are just a few pictures from the field. I’ll bolster them with a prosier post as soon as I can.

Here’s our quarry, Anolis sagrei, the “festive” anole.

IMG_4709

And here’s one with dewlap unfurled.

IMG_4747

This was Rob’s first time catching Anoles. Here’s his face after his first successful lasso.

IMG_4679

Three days later he was catching like a pro while reposed under thorn bushes.

IMG_4698

We’re catching a lot of lizards for this study – 120 per island. Here are a few in a lizard bag waiting for sorting.

IMG_4702

While we’re catching lizards we’re also gathering data on their behavior and ecology – where they’re piercing and how warm that perch is for example. Here are Raph and Rob typing in some of the data. We’ve got well over 600 observations so far.

IMG_4703

We’ve been doing a bit of driving between sites. Not a problem though with scenery like this. Note, the steering wheel is on the American side but the roads are all reversed (Thanks Great Britain). This causes some consternation trying to get used to the unfamiliar lane position with a familiar vehicle layout. Oddly, 2 of the 3 cars I’ve driven this trip have been reversed in this way. This however was the only car with a helpful red arrow to remind me where to be on the road. Luckily for these dirt paths it’s one car at a time no matter the side.

IMG_4715

We’ve met a few other friends in the field. Here’s Geoff with a racer snake we found in the forest.

IMG_4773

And here’s Anolis angusticeps, the coolest, most secretive anole we’ve seen this trip.

IMG_4682

Here’s the final stage – a giant cooler in the back seat of a small sedan to the airport. Just peeking over the cooler in the back there is Jon, the ringer for lizard catching.

IMG_4803

Bimini is our next stop for tomorrow! One more push on fieldwork, another ten dozen lizards, and then it’s back to Boston.