Predators on the Ecotone!

Light coloured male Collared Lizard (Crotaphytus collaris) temporarily in captivity

We're always interested in potential predators of lizards at White Sands- especially considering predation on mismatched, non-camouflaged lizards was probably an important selection pressure for crypsis (matching the white background). Usually the only signs of predators we observe are some scattered roadrunner tracks (it seems the populations of other winged reptile predators, shrikes and kestrels, have declined in the area).

Two days ago, I was pacing around a scrubby 'marginal' dune site and what I immediately thought was an oversized H. maculata, dashed bipedally towards a small cottonwood tree at the edge of a dune. I yelled at Mikki that I just saw something HUGE and I thought it was a Gambelia because of the size. We stalked up to the tree and Mikki pointed out a large A. inornata and suggested maybe that was what I saw. Pssh, field assistants, I thought. This dragon had a huge head and stood like four feet off the ground. Er, well, maybe four inches. Anyway, after a few minutes we were turning our backs on the cottonwood to hunt down less menacing creatures, when Mikki looked back and said she saw something HUGE on the dune. Now, I need remind you that when you're hunting dragons of a miniscule size (2 inches, 5 cm), anything > four looks mighty formidable. Well, we went after that beast of a lizard, soon discovering that it was a very lightly coloured male collared lizard- rarely seen this far into White Sands. Collared lizards have large heads for their size and a bite force to match. Perhaps it was my fear of being attacked by this chipmunk-sized reptile that made us take nearly forty-five minutes to catch the fellow. Or, it could have been something to do with our lack-of-water-induced exaggeration-hallucinations.

First of all, I had to create a new noose. Usually we use a 1.5 cm diameter slip-knot loop at the end of a pup-fish pole to capture lizards. I had to fashion a new, 4 cm noose to better accomplish the task. Turns out, getting a dental floss loop over something that large is actually pretty easy, and as I was pulling him out of the branches, my pole all a bent, his mouth all open, I thought, okay, what am I going to do with this biting machine?

So second I put him on the ground all tangled in floss and in quite a rage. As sort of a test I offered him the brim of Mikki's hat. Yeah. He chomped right into that and didn't let go. Well that made it easier. I wrapped my hand around him securely, thumb and forefinger pressing his jaws down onto the hat. I tried to loosen the noose around him, but quickly realized with the hat in his mouth, I could only get so far. So I remembered stomach flushing lizards last field season and how I used a toothpick to keep their mouths open while I induced them to barf... I took a thin stick and wedged it between his upper and lower jaw like a horse-bit. I then could get the loop over his head and drop him quickly into a cage.

We're going to take a tail tip (for genetic work), some colour specs and photos of our vicious fellow before returning him to the interdune. He was quite light for a collared lizard, and it will be interesting to see if he is unique genetically and morphologically. Perhaps these small-lizard predators are finally encroaching on the White Sands...


PS. Mikki saw ANOTHER light collared lizard in the same interdune today! The first is still in captivity, so we know that there is more than one possibly chomping on our study species!

Et. al. ~ Why my field assistants are the best ever!

Travis Morgan hiking up a dune just before sunset- pole at the ready!

Yes, it's that time. My assistants are fledging and often times out-catch me. Yesterday I sent them out alone to do some lizard noosing while I prepared a presentation for an outreach project. I sent them out with ten cages- we had only once caught ten lizards in a day before. Well. They showed me. They returned after only three hours with twelve individuals! They made an awesome make-shift cage out of a large water bottle poked with holes. 

Mikki Brinkmeyer showing off her mad noosing skills in the bushes.

So I ask myself- why do I go out at all? Why not retire in the cool apartment and wait for them to deliver the little friends to be processed and prodded? Well, turns out I need to work on my tan.

Here's to awesome field assistants!

~Simone

The Start of June

Just released male H. maculata at sunset.

We're roughly half way through the first part of our field season. We're up to 79 lizards- and hoping now for 150 before June 20. We had our best catching day today with 10 lizards!

I'll write again soon, but for now I have to sketch a Holbrook for some awesome slide shows!
~Simone

The Beginning

I've experienced some delays getting this blog up and off the ground- but I'll try my best to fill you in on our first two weeks.

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The purple clouds finally descended on Otero County and the local grocery store parking lot. It has been four months without rain in the Tularosa Basin. As I write, acres of gypsum are dissolving on the surface of  White Sands... encouraging hydrophiles everywhere to crawl up from the depths of drought. The last few days the humidity has become more and more apparent. The air clings and so do the tiniest little flies who seem to bite everywhere from behind the ear to the arch of the foot. My supervisor, Luke Harmon's words ring true- insects aren't good for anything except food for lizards!

Handful of New Mexican Spadefoots (spadefeet? Spea multiplicata) who came up with the rains last year at
 Jornada Long Term Ecological Research Center

During a blog-writing break, we ventured outside and I snatched this little Mediterranean House Gecko (Hemidactylus turcicus) from the wall outside the apartment. While harmlessly identifying his sex, he quite suddenly and unexpectedly dropped his tail in my hand- right up to the base! The tail flopped around on the ground for minutes before we returned our little stubby friend outside. I felt a little guilty, but he's a bit of an invader anyway (yes, he.) 

We have captured, measured and marked 54 Holbrookia maculata on the ecotone between White Sands and the Chihuahuan Desert. To be honest, after nine or so full days of catching- I expected to have more lizards. To me, ecotone animals seem flighty, suspicious and less conspicuous than their counterparts in the heart of White Sands. Certainly, there are more birds, lizards and mammals on the ecotone, as evidenced by noisy chatter, numerous tracks and occasional sightings.

Common Nighthawk (Chordeiles acutipennis) Mikki spotted beside our ecotone site. Nighthawks are insectivores, usually feeding on moths at night.

Due to the lack of lizards we've seen on the ecotone, we may be moving on to sample further in the dunes where H. maculata is abundant. We'll spend at least one more day on the edge of White Sands returning lizards and scouting around. 

~Simone