Snakes!

Evening,

It is always exciting to see potential predators in or around our field sites. Snakes- rattlers, gophers, coachwhips and others usually leave behind only their sinuous tracks left from nightly excursions... but very rarely we are fortunate enough to witness these symbol-laden ophidians. Earlier this season, each of my field assistants was fortunate enough to glimpse the flash of a snake. Isaiah saw a dark black s stretch across his path in the first week we were out at White Sands... we never found out what species the creature was. Last week, Mikki and Jackie saw what they later confirmed was a very large coachwhip. I was a little disappointed that I had never seen a snake out at White Sands (in all my years- I only ever saw rattlers and racers in our dark soils sites and on the nearby lava flow). Finally, the overcast skies tempted out two of our legless friends...

First, the most beautiful snake I have ever seen, and the only rattler I have viewed atop white gypsum sand... coiled into a ball the size of my fist, and quietly curled in the shade of a bush (mental note to not go digging through said bushes for lizards)... the smallest rattlesnake I have ever seen. Unfortunately, we did not have a camera ready for a photograph, so I was forced to do as the Naturalists of old and make a quick sketch from memory:

Mystery Rattler. 

I have not been able to find and identify this snake in any field guide or online image source. Most rattlers, it seems, have a light base colour with darker diamonds or patches along their dorsal line. My snake had the deepest black-green pigment with bright cream splotches that seemed to almost glow in the cloudy day. The snake was small and probably a juvenile, but she quickly showed her namesake rattle, and without a sound or shake (despite my 'animated' sketch) slithered silently into the brush.

And second... a less exciting, but far easier to photograph... gopher snake was the 'victim' of many naturalist paparazzi outside the White Sands National Monument visitor centre. At first coiled up under a yucca shrub, she quickly became impatient and relocated across the path to another larger and more private shrub. Although I nearly treaded on her during her short trek, I was able to snap some shots of this gorgeous creature:

Snakes aside, we have had a busy day, and will again tomorrow as we are leading full-day lizard ecology and evolution outreach programs for children in the Alamogordo area. I'll devote an entire post to our exciting kids-days so stay tuned!
Until then, goodnight serpents!
-S. Des Roches

Camping, Dark Soils, White Sands Symposium

Well, I've certainly let the time and events build up since I last wrote. I'll therefore be brief and let the photographs speak the stories!

Insect and spider hunting with the whole team.

Last week our advisor, Erica Rosenblum, visited with her new post-doc, Christine Parent so we took it upon ourselves to spend the night under the faint stars and bright full moon. We also did a little entomological collecting and stalked spiders and camel crickets (and an occasional wind scorpion).

The night brings out the very small...
"Wind Scorpion" consuming a less-interesting dipterid

... and the very large full moon.

"Dark" melanic conspecific of the same species of
little striped whiptail (Aspidoscelis inornata) also
found in White Sands.

On our way to the first ever White Sands Symposium in Las Cruces, we stopped by our "dark soils" site at the Jornada Long Term Ecological Research Station. I've collected melanic (dark pigmented) lizards from this site in years past, which are conspecific (depending on who you ask) with the blanched species found within White Sands. This year, we glimpsed some long-nosed leopard lizards, many dark little striped whiptails, one dark lesser earless lizard, and several side blotched lizards.

Requisite jumping-with-noose-poles photo at Jornada.

We stayed in Las Cruces for two nights during the premier White Sands Symposium. Our advisor helped organise the event and we all enjoyed the various talks about dune dynamics, entomology, mammals, and of course, lizards of White Sands.

White Sands Symposium at Las Cruces, NM

I will probably post again tomorrow as we've spotted some exciting animals at our sites recently. We also have an outreach program for local kids on Thursday and Friday. Hopefully the natural selection game I made up last year will 'work' again!

Take care followers! And goodnight creatures of the dark!
-S. Des Roches

The One Hundredth

 Lizard 100 captured today!

Some 'intense' preparation going on in the back of
my little car.

Today marks the day of the 100th lizard (thanks Isaiah, who nabbed that little H. maculata in the early afternoon. Yes, we are combining the numbers of two species (61 Holbrookia maculata, and 39
Sceloporus undulatus), but still, a cause to celebrate by going out for supper at a 'generalised' Asian cuisine common to small American towns. Believe me, I'm not knocking it. I definitely get a 'general' craving for sushi, curry, and pad thai after so much (New) Mexican food.

Jackie feeling the euphoria of ice cold water
down her back.

It was a pretty hot day today and missile testing (much of White Sands, and indeed southern New Mexico state is a US bombing and rocket range... the largest military installation in the country) prevented us from getting to our sites before 10:30 am. Hence we stayed out a little late today and had to bear the real heat of the windless day in the early afternoon.

Earlier this week we also pre-celebrated and ventured up to the Sacramento Mountains South East of the Tularosa Basin and dined in Cloudcroft. It is always an exciting shock to see the abrupt transition from the dry desert to the pine and fir dominated forest on the wetter side of the mountains.

Our most prolific interdune site for H. maculata... especially for its size. Only 30,000 square meters and over thirty lizards captured each field season.

Zooming out to a view of White Sands, which appears as if a lake, from Cloudcroft in Lincoln National Forest.

Tomorrow we finish our first set of interdunes - the "Admin Road" site (so named because these are just over from a road that starts behind the White Sands National Monument administration building). This weekend we will move on north-east to the larger interdunes at the "Dune Life" site (after the Dune Life visitor trail).

Good night 100th lizard!
-S. Des Roches

Recapture Recapture Recapture!

Good Evening!
Well it has been a very busy few days... but I think it is about time I sketch out an overview of my current project for those of you who are yet unfamiliar.
Previously, my research focused on the ecology side of adaptation - especially habitat use and functional morphology (linking lizard's traits with how they perform - eat, bite, escape predators, and sprint).

The little striped whiptail (A. inornata) with a tasty, grubby snack under the shade on the ecotone of White Sands and the surrounding Chihuahuan Desert.

For her doctorate degree, one of my advisors, Erica B. Rosenblum, researched parallel adaptation of three species of lizards to White Sands. She found that not only do the three species show directional change in colour (they are more 'blanched' on White Sands), but they also generally have longer legs and broader heads for their body size. My results from two years ago also demonstrated that White Sands earless and whiptail lizards were larger than their darker counterparts living in the dark soiled Chihuahuan desert.

Jackie and Mikki checking out a muddy puddle outside the ecotone of White Sands.

For my current project, I am examining whether there is current natural selection on lizards living on the ecotone of White Sands. But HOW? We are using mark-recapture to determine whether lizards with certain traits (colour brightness, head size, limb length...) are more likely to survive from one capture event to another. We mark the lizards using elastomer tags (a fluorescent plastic polymer that I inject with an insulin needle just under the lizard's skin) and generate unique tags using five colours in four locations on the lizards' little bellies. This way, we can measure each lizard's features and keep track of each individual over subsequent capture events. If we do not recapture a lizard, it is likely it has died within the time since the last capture... there is of course, some chance a lizard has just wandered further away. By recapturing multiple times, we can increase our chances that we will find such distant travelers... and be more certain that we are accurately measuring differential survival in our sample populations.

Last year, we began the mark-recapture experiment on the lesser earless lizard, Holbrookia maculata.  We first sampled in May-June, and then recaptured in August. We had about a 60-70% recapture rate... meaning, we 60-70% of the lizards we captured in August were already tagged and had survived since the spring.

A male lesser earless lizard (H. maculata) after just being released. The black dot on his tail is another mark to show us that he has already been caught this time around. The mark is just done with Sharpie and will wash or shed off in a few days. The elastomer marks, however, are inert and mostly permanent, and can hardly be seen in daylight even when the lizard is viewed from below.

Our results from last year already showed some interesting patterns... lizards increased in condition (weight per body length) over the summer (as they fattened up in preparation for the autumn), lizards with higher condition in May-June were more likely to be recaptured in August, and finally, lizards that were brighter in May-June were also more likely to be recaptured. Further work this year will help us confirm whether brighter (whiter) lizards in better condition are more likely to survive on the ecotone.

Mikki readying her noose at our site, "AR02" (Admin Road 02)

This year, we are continuing our work with the earless lizard, and we have added the eastern fence lizard, Sceloporus undulatus to our study. So far we've  captured 13 fence lizards and 38 earless lizards, 24 of which were survivors from last year! It's shaping up to be a great field season... more next time on our locations and more stories from the field!

Goodnight 8 H. maculata and 7 S. undulatus sharing our apartment tonight...
-S. Des Roches