Back at it!

Well, it certainly has been a while!

Last I blogged about our Outreach day- which of course, was a blast. We finished up the last few weeks of the beginning-of-the-activity-season-field-season-part-one shortly after our kid's outreach days. Overall, we had fairly a fairly successful recapture rate for Holbrookia maculata... which was, funny enough, almost exactly 50%. We finished the field season with 175 successful captures, 87 of which were previously tagged from last year- either in the beginning or end of the activity season in 2011. We captured 145 Sceloporus undulatus and tagged every single one.

Male Lesser Earless, H. maculata, on the ecotone

Female Lesser Earless, H. maculata, in the heart of White Sands

We also chanced upon some exciting other finds... which may be considered predators roaming around our interdune sites!

Male Collared Lizard, Crotaphytus
collaris, we named"Tyrone Lizardser,"
 for obscure, irrelevant reasons 

Gopher Snake, Pituophis catenifer, basking
between two interdunes on the ecotone

We have now just started the second recapture of S. undulatus and have decided that three weeks is not enough time to sufficiently sample H. maculata as well. So far, our recapture rate is not as good... after two days, we've collected 32 lizards, only 8 of which... or 25%... are recaptures.

Beautiful little Eastern Fence, S. undulatus, looking a little miffed at
being poked, prodded, and "processed"

Does this say something about the biology or ecology of this species? Is our study going to be effective at measuring natural selection by mark recapture over two years for S. undulatus? Whether or not we will be able to gauge the strength and direction of selection on this species, is yet to be determined... however, at the very least we can obtain informative population data, discover something about the robustness of mark-recapture methods for measuring natural selection across species, and spend just a few more weeks in the sun chasing after reptiles!

My favourite shot of an Eastern Fence Lizard just hanging out.

Until next time,
S. Des Roches

Outreach: White Sands

Good afternoon!
Well, it is about time I spoke a bit about our adventures putting on our outreach program last week. On Thursday and Friday we led a "Lizards of the White Sands" day camp for local kids ages seven to fourteen as part of the White Sands Institute (which is an organisation that runs various classes for the public to enjoy the national monument).
This year is our second year running the event so fortunately we had a working schedule:


I. Introduction to White Sands, lizard ecology, and evolution.
II. Pack up with lots of water, sunscreen, and sunglasses to go out to the dunes.

Isaiah, Mikki, and I before the Natural Selection Game.

III. Natural selection game:
I divided the group of kids into 1/3 Roadrunners, or "Predators," and 2/3 Lizards, or "Prey." (on the first day, we had 21 kids - 7 predators, 14 prey; on the second day, we had 12 kids - 4 predators, 8 prey... much more manageable)...

Before the game.

Explaining the rules.

We picked an enclosed interdune where the Lizard-kids were given two dark-painted lizard toys, and one white-painted lizard toy to hide in various locations - under bushes, in the open, and on top of yuccas. I told the kids to make sure they remembered where they set their models. While the Lizard-kids were placing their basking models, the Roadrunners had to turn around and close their eyes (no cheating!). 

Ready to let the kids loose for the game.

After the kids had placed all their models, the Roadrunners had less than a minute to gobble up as many lizards they could find (I had to cheat a bit myself and check how many models they had in their hands before calling them back)... i.e. selection. 

Now... the tricky part... after the Roadrunner-kids' return, I sent the Lizard-kids to go check and see which lizards survived the feast. I then gave Lizard-kids one lizard toy of the same colour for every one they had left to indicate reproduction and inheritance. After their return, it was again the time for the Roadrunner-kids to feast as another round of selection. We played for only two generations... but I imagine with a greater proportion of prey-to-predators the game could go on for many more (our lizard population depleted pretty rapidly as a result of high predation). 

Go Roadrunner-Kids!

To drive home the entire point of the game, I then asked all players- Lizards and Roadrunner-kids to go collect all lizard models that remained in the interdune and pile them up in front of me. I asked all the children how many dark and how many white lizards were out to begin with. On the first day, with 21 kids, we had 14 x 2 = 28 dark lizards and 7 x 1 = 7 white lizards... i.e. the ratio of 2:1 dark:white.

Setting out lizard models.

Laying out the day's catch.

At the end of the game, we had the same number of dark and white lizards - 9 of each. I explained that this is how we think white lizards came to be on White Sands, via natural selection. 

Explaining natural selection.

This process takes many generations (where the lizards have babies like themselves), which is why you don't see white lizards taking over rapidly after only one reproduction event - they increase in proportion gradually; over time there are more and more lizards that match the white gypsum substrate of White Sands, or camouflage, and fewer and fewer that stand out.

IV. Catching the three species and learning about their ecology

What were the lizards doing when you first spotted them? What is the shape and colour of each species? How do you tell a male from a female?

Kayla showing her troop a little striped whiptail.

V. Return from the dunes and observe the lizards closer, and if time permits, try noosing some of those lizard toys!

The three funniest comments from the two days? (embarrassingly two came from my mouth):

3. (during my introduction talk) Me: "White Sands is very very young compared to the age of the Earth... it is only about 6,000 years old."; Kid: "So it's like a baby?"; Me: "Yes, White Sands is a geological baby"
2. (after drawing a horned lizard on a sheet of paper) Kid: "How big are those lizards?"; Me: "Oh about the size of your fist"; Kid: "So... like the size of a hairball... like a cat's hairball?"; Me: "Uh, sure..."
1. (when describing ecology in White Sands) Me: "Lots of predators eat lizards... roadrunners, snakes, shrikes, large lizards."; Kid: "Would a coyote eat a lizard?"; Me: "Well, maybe if they were desperate... but lizards are really small compared to coyotes and it may not be worth it for the coyote to chase around such a small meal... it's like if you were to run around after a Cheeto."

Participants showing off their lizard mugs.

We also gave the kids fantastic mugs that our advisor Erica Rosenblum had made featuring my design!

As usual we had a fantastic time with the kids- definitely one of my highlights of the summer. We are certainly fortunate to work in White Sands where we have the opportunity to put on such outreach programs! Thank you to my assistants, Isaiah, Mikki, and Jackie for helping me out this year, to David Bustos and Joan Griggs for doing the logistical work and advertising to get the camp running, and finally to my advisor Bree for letting us take charge and providing the foundation for the program!

Good day for now! Only one catching day left! Stay tuned for a season-recap and some photographic highlights!

-S. Des Roches

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