USGS Desert Tortoise Project: Part 3

Dedicated exclusively to field herping.

Moderator: Scott Waters

Post Reply
User avatar
Zach Cava
Posts: 243
Joined: June 7th, 2010, 7:27 pm
Contact:

USGS Desert Tortoise Project: Part 3

Post by Zach Cava »

Sorry if you don’t like flowers, cause they outnumber the herps in this post! I’ve decided to start including range maps for all herp species I post, courtesy of NatureServe Explorer. Keep in mind, though, that these distributions do not differentiate subspecies’ ranges, and only species’ U.S. ranges are shown. As always, corrections/additions are encouraged.




Goldfields (Lasthenia californica)

Image


Image


Image




Someone’s secret desert gardening project?

Image




Lupine (Lupinus sp.)

Image


Image




My first Mojave Green Rattlesnake (Crotalus scutulatus scutulatus). I spotted this one stretched out on the side of the road as we were driving by. These are the most commonly encountered snakes out here, and we have to drive carefully as they (and other animals) like to hang out on the dirt roads.

Image


Image




Range of C. scutulatus:

Image




Sunset in the desert

Image




Yellow/Desert Evening Primrose (Oenothera primiveris)

Image


Image




A tortoise with a really funky shell. Congenital scute anomalies are fairly common in desert tortoises, but incidence may vary significantly by locality. Factors influencing the development of scute anomalies may be environmental (temperature, moisture levels, oxygen content, presence of chemical pollutants/radiation at the nest site), genetic, or both (see Grover and DeFalco 1995 for summary).

Image




Coyote skull (Canis latrans) on dry lake bed. Coyotes are one of the few species capable of preying on adult tortoises. Although coyotes prefer to eat mammals (rodents and lagomorphs), it is thought that they become less selective if such prey is not abundant (i.e. during drought years), and consequently tortoises may experience heavier predation during these times.

Coyotes are “subsidized predators,” meaning they flourish in urbanized areas where human resources allow them to reach exceptionally high densities. So, it is not surprising that recent studies have shown a positive relationship between coyote predation on tortoises relative to human population. For more on this, see Esque et al. 2010.

Image




Mojave Sun Cup, aka Field Primrose (Camissonia campestris)

Image




2nd rattler encounter - C. scutulatus is a dangerous animal. First off, while I hesitate to use the word “aggressive” (“tending toward unprovoked offenses”), there is no question that Mojave Greens are very easily agitated relative to other venomous snakes. Secondly, the species produces some of the most toxic venom of any snake in North America, which is unusual in that it functions as both a neurotoxin (attacks the nervous system, causing paralysis which can lead to cardiovascular/respiratory failure) and hemotoxin (attacks the circulatory system, causing necrosis).

So we watch where we step. (Though from my experience they seem to sense our presence well before we do theirs, and they do a great job at making themselves known. I think it would be difficult to surprise one).

They feed on small mammals (especially kangaroo rats), lizards, snakes, and birds.


Image


Image


Image


Image




A beautiful canyon, one of the many randomly generated sites for a tortoise-searching transect (this photo does not come close to capturing how colorful the rocks were). It’s always fun going on these searching missions, because often times we’re sent to (virtually) uncharted areas, and you never know what you’re gonna get.

Image




Down inside the canyon

Image


Image




Golden Evening Primrose (Camissonia brevipes)

Image




Fremont’s Pincushion, aka Desert Pincushion (Chaenactis fremontii)

Image




Chia (Salvia columbariae). Used by Native Americans for food and medicine (for more info go here).

Image


Image




Bladderpod (Isomeris arborea)

Image


Image


Image




Mojave Aster (Xylorhiza tortifolia)

Image


Image




Desert Five-Spot (Eremalche rotundifolia)

Image


Image


Image




Thistle Sage (Salvia carduacea)

Image


Image


Image




Spiny Hopsage (Grayia spinosa)

Image


Image




Brown-Eyed Primrose (Camissonia claviformis)

Image


Image


Image




Yellow Pepper-Grass (Lepidium flavum)

Image


Image


Image




Small Desert Star (Monoptilon bellidiforme)

Image




Male tortoise (right, with radio) courting unmarked female. We’ve found quite a few new tortoises this way.

Image




Image




Inspecting the camera

Image


Image




Purple Mat (Nama demissum)

Image


Image


Image




Cool seed-sphere

Image




A young (but equally pugnacious) Mojave Green. Females give birth to 2-17 live young July-September. Adults may reach lengths of 24-51 in (61-129 cm).

Image


Image




Coachwhip, aka “Red Racer” (Masticophis flagellum piceus). These snakes are fast, and for that reason these are the best photos I could manage (and I was only able to get these because it was early and this one had not yet completely warmed up).

Image




Coachwhips are long and slender (36-102 in; 91-260 cm), and possess scalation resembling a braided whip, for which they were named. Of all snakes populating the Mojave, coachwhips are among the most heat-tolerant, and are more likely to remain active at times when other species are seeking shelter in the shade. Their diet includes small mammals, birds/eggs, lizards, snakes, frogs, young turtles/eggs, insects, and carrion. If threatened they usually attempt to escape to a rodent burrow or hide in the branches of a bush (as this one did). However, they can be aggressive if cornered.

Image


Image


Image




Range of M. flagellum:

Image




Mojave Shovel-Nosed Snake (Chionactis occipitalis occipitalis). This was an exciting find for me. Shovel–nosed snakes are small (10-17 in; 25-43 cm), and nocturnal. They generally remain burrowed underground during the day, so I was surprised to find this one out and about in broad daylight. In contrast with other burrowing snakes that “tunnel” through loose substrate, C. occipitalis is instead adapted to “wriggling,” and is aided by smooth scales, a shovel-shaped snout with an inset lower jaw, nasal valves, and a concave abdomen (see photos). They eat insects/larvae, spiders, scoripions, and centipedes.

Image


Image


Image


Image


Image


Image


Image


Image


Image


Image



Range of C. occipitalis:

Image




Desert Larkspur (Delphenium parishii)

Image


Image




Cool rocky slopes

Image




Image




Desert Globemallow, aka Apricot Mallow (Sphaeralcea ambigua)

Image


Image




Someone’s been leaving half-eaten animals around. I think the first one is a kangaroo rat (Dipodomys sp.).

Image


Image




Great Basin Gopher Snake (Pituophis catenifer deserticola)

P. catenifer is a wide-ranging species (see map below), capable of surviving in a variety of habitats. While their appearance (which may vary significantly by locale) bears only a superficial resemblance to a rattlesnakes’, when threatened they often adopt a rattlesnake-like attitude by standing their ground, flattening their head, hissing, and vibrating their tails (see photos).

While this impression serves an adaptive purpose in fending off potential predators that may fall for the trick, today it probably also results in many gopher snakes being killed by ignorant rattler-fearing humans (not to mention their intimidating behavior won’t help scare away cars). Gopher snakes are in fact non-venomous, and subdue their prey (rodents, rabbits, moles, birds/eggs, lizards, insects) by constriction.

Gopher snakes are active mostly during the day, except in extreme heat. This one was in the middle of the road, and was kindly moved out of the way by some conscientious commuters.

Image


Image


Image




Range of P. catenifer:

Image




Great Basin Whiptail (Aspidoscelis tigris tigris)

Whiptails are one of the most abundant lizards here in the Mojave, but they are very quick, and I usually just catch a glimpse of them running from one creosote bush to another. They eat insects, spiders, scorpions, and other lizards.

Image


Image




Range of A. tigris:

Image




Juvenile Desert Iguana (Dipsosaurus dorsalis)

Desert Iguanas are one of the larger lizards we have out here, though this one was just a baby. They are mostly herbivorous, and will climb the branches of creosote bushes and other plants to get at leaves, buds, and flowers, though they will also eat insects and carrion. They are very heat-tolerant, and more likely to be active on days too hot for other lizards. Desert Iguanas breed in April-July, and females lay a clutch of 3-8 eggs June-August.

Image



Range of D. dorsalis:

Image








ATV-ing is a popular activity out here, and I was told this trail is one of the most favored spots to do it – I could see why.

Thanks for looking,

-Zach








Image




Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
User avatar
chris drake
Posts: 193
Joined: June 13th, 2010, 1:51 pm
Location: Sugar Land Tx

Re: USGS Desert Tortoise Project: Part 3

Post by chris drake »

That gopher is outstanding!! Very nice post. Gotta love some of the desert flowers. I take pics of them too.

Image

Chris
User avatar
Carl Brune
Posts: 488
Joined: June 7th, 2010, 11:22 am
Location: Athens, OH
Contact:

Re: USGS Desert Tortoise Project: Part 3

Post by Carl Brune »

Nice post. No problem with the flower shots.
User avatar
FLjeep74
Posts: 76
Joined: June 7th, 2010, 9:47 am
Location: West Central Florida

Re: USGS Desert Tortoise Project: Part 3

Post by FLjeep74 »

That Gopher Snake is beautiful! It's neat to see so much color and 'life' growing in the deserts... from someone who's never been out west it's not the first thing I think of when I think of "dry, sand, rocks, mountains" lol.

Very cool and enjoyed the explanations accompanying your photos.

Thanks for sharing,

Mike
User avatar
herpseeker1978
Posts: 1139
Joined: June 7th, 2010, 8:05 am
Location: Albuquerque

Re: USGS Desert Tortoise Project: Part 3

Post by herpseeker1978 »

love that faded pattern on the gopher!

Josh
btskanks
Posts: 47
Joined: June 20th, 2010, 8:37 am

Re: USGS Desert Tortoise Project: Part 3

Post by btskanks »

-Thank you much! I didn't know how beautiful it could be, that gopher snake is the bomb! The front of my sulcatas look just like the torti in the pics!
User avatar
klawnskale
Posts: 1211
Joined: June 7th, 2010, 7:09 pm

Re: USGS Desert Tortoise Project: Part 3

Post by klawnskale »

I have really grown to hate invasive Arabian Grass (Shismus) It is so bad for species that love loose, duney sand like horned lizards, fringe toeds and zebra tailed lizards. Damn stuff is everywhere! The red grass in some of your shots is Bromus rubens, (Red Brome) which thank goodness for the small things, is native.
Gordon C. Snelling

Re: USGS Desert Tortoise Project: Part 3

Post by Gordon C. Snelling »

According to the Calflora website Red Brome is also a nonnative.
http://www.calflora.org/cgi-bin/species ... ecnum=1209
Jackson Shedd
Posts: 147
Joined: June 7th, 2010, 5:48 pm

Re: USGS Desert Tortoise Project: Part 3

Post by Jackson Shedd »

klawnskale wrote:The red grass in some of your shots is Bromus rubens, (Red Brome) which thank goodness for the small things, is native.
Yikes! Where were you told this? Red brome is a non-native invasive that has been pegged as one of the main plants that has drastically changed natural fire regimes in our deserts, which is also one of the many, many causes of desert tortoise declines.
User avatar
Greg Knoell
Posts: 6
Joined: April 18th, 2011, 10:05 am
Location: Phoenix, AZ
Contact:

Re: USGS Desert Tortoise Project: Part 3

Post by Greg Knoell »

I usually just browse the forums but had to post...beautiful pics!! That sonoran gopher is outstanding, certainly looks to be a hypomelansetic color mutation/variant. I'm a Pituophis fan so had to comment. I've been on a few of the desert tortoise surveys with AZ G&F, lots of fun. Looks like you had a very productive outing!!

Greg
User avatar
klawnskale
Posts: 1211
Joined: June 7th, 2010, 7:09 pm

Re: USGS Desert Tortoise Project: Part 3

Post by klawnskale »

Yikes! Where were you told this? Red brome is a non-native invasive that has been pegged as one of the main plants that has drastically changed natural fire regimes in our deserts, which is also one of the many, many causes of desert tortoise declines.[/quote]
Sorry my bad. That's what happens when I'm expected to learn about plant species in the Mojave Desert in 2 weeks what some biologists have taken decades to learn. Too much info to process and remember at all once.
User avatar
Brian Hubbs
Posts: 4735
Joined: June 7th, 2010, 11:41 am
Location: "Buy My Books"-land

Re: USGS Desert Tortoise Project: Part 3

Post by Brian Hubbs »

Nice post Zack. You must be getting addicted to CA...
Zach_Lim
Posts: 1607
Joined: June 10th, 2010, 8:37 pm

Re: USGS Desert Tortoise Project: Part 3

Post by Zach_Lim »

That is one GORGEOUS pit!
User avatar
Fundad
Posts: 5721
Joined: June 7th, 2010, 7:11 am
Location: Los Angeles County
Contact:

Re: USGS Desert Tortoise Project: Part 3

Post by Fundad »

That Gophersnake is Beautiful..

Fundad :shock: :thumb:
Post Reply