Wednesday, April 29, 2009

Come Visit, Then Leave

Plants use flowers to communicate with aliens. Over eons of meticulous research, the most creative plant families have developed countless new and intricate products. Each floral brand is refined to most effectively capture the attention and to direct the visitation of a specific sector of the mobile animal population - bees, flies, moths, ants, beetles, rodents, bats, birds, etc. - or the mobile inanimate vectors of wind and moisture.

These colorful products are embedded with coded messages to influence their target audience. The simple part of the message is "Come visit. Then leave."
Plants post billboards of brightly colored petals, some done up in infrared hues that are only visible to the compound eyes and rudimentary brains of insects. Refreshments might be offered as further enticement. In the front lobby, there are billowing columns of pollen. For the more discriminating patron, nectar glands are hidden deep within the recesses of the florid establishment. Some plants even offer honeydew-colored aphid slaves for ants to harvest and move about the plant kingdom. As far as I know, musical entertainment is not offered by flowers.

Meanwhile, the unwitting alien visitor is tricked into doing the plant's bidding: "Fertilize my intimate plant parts so that I can reproduce and spread."
Sometimes, controlled timing of the blossoms or trapdoor apparatus on these attractive flowers manipulate alien visitors to bring pollen from another plant rather than allow self-pollination. In this way, the plant stealthily refines its message and furthers its goal of reproducing and even to adapt over generations into a new design.
Humans tend to misinterpret the messages of wildflowers. Most humans are innately attracted to the colors and scents of wildflowers, and assume these complex designs are created for their human enjoyment. The ungodly among us strip the flowers into their functional parts (petals, sepals, pistils, stamens), count and measure the parts, describe small details and then organize the wondrous variation of wildflowers into human-defined families, genera and species. Humans of a spiritual bent see God's hands and gifts in the fascinating complexity, ecological persistence, inspiring beauty and mystery of wildflowers.
Yet humans are only able to see, smell, taste and feel a small fraction of the intricate and minute detail of the floral world. Basically, humans don't get it - flowers are highly evolved rituals of plant sex and the only role humans play are to occasionally assist in the hand-off, which, by the way, fairies are better at.
In order of appearance:
common popcorn flower, Plagiobothrys nothofulvus, Dipper Ranch, April 2009
gum plant, Grindelia sp. and beetle, north of Salt Lake, Utah, 2006
checker lily, Fritillaria affins, Rancho San Antonio Open Space Preserve, 2002
pipevine, Aristolochia californica, Angel Island, March 2009
arroyo lupine, Lupinus succulentus, Dipper Ranch, April 2008
California poppy, Eschscholzia californica, Dipper Ranch, April 2008
currently unidentified fairy, Dipper Ranch
Chinese houses, Collinsia heterophylla, Bear Valley, Colusa County, May 2003

Tuesday, April 21, 2009

Snake Weather - Part 1

Please note: my niece who is visiting me in California this July is not allowed to read this blog post. She says she will not visit the Dipper Ranch because she "doesn't do mice and snakes", but I can meet her in San Francisco. This young lady grew up on a farm - what's the deal? I guess I could also forbid my mom and youngest sister and some of my botanical colleagues from reading this post because they too are freaked out about my snake stories.

Dear friends & family - please reconsider. Snakes are very interesting. Did you know that snakes have two lungs like us, but usually, in order to fit inside their unique body shape, the right lung is long while the left lung is shrunk to nothing kinda like our appendix? In any event, before you proceed further, I must warn you that this blog posting includes moments of venomous snakes, rattles, screaming and the death of a baby bunny. Kinda like those TV nature shows.

Snake weather is any pleasantly warm day when it's been cold, any moderately warm day when it's been hot, and any warm night. We had daytime temperatures in the 80s and 90s for several days in coastal California. Quite unusual for April when we usually have either bright warm days or cool fog drifting among the spring-green hills. Last year, it wasn't until May that we had several consecutive hot days and that's when the snakes suddenly showed up. I proclaimed May 12 through 18, 2008 as "Snake Week" because I saw an average of 1 snake per day around the farmyard. I could have also called it "Brown Snake Week" because they were either gopher snakes or rattlesnakes, or "The Barn is a Snake Pit Week", but that was in the early days when I didn't have enough experience to classify the week by subcategories.

In early April this year, my cuddly ranch cat, Cole, brought me baby bunnies. The first one was alive and I released it from his clutches; the second one was dead. Cole and I had a talk. I explained he is allowed to hunt all forms of rodents in the farmyard, especially those that come into the house, as part of the Dipper Ranch snake protection program. That is, by reducing the rodent population, he would be removing the attraction of the house and farmyard to predators and thus protecting us from snakes. I also explained that rabbits are lagomorphs (gnawing, herbivorous mammals including rabbits, hares, and pikas), not rodents, and thus they are not included in his hunting license. I showed him the bell that would otherwise go on his collar. Cole nodded wisely and went back to monitoring the gopher holes.

One week later when I was chopping up enemy #1 - thistles, I noticed Cole happily purring by the kitchen door. When I reached down to ruffle his cheerful fur, I realized there was another baby bunny laying on the ground at his feet. Furious, I dragged the 15-lb feline indoors. After a brief struggle, he was subsequently decorated with a bell on his collar. A jingly Cole followed me outside to the scene of the crime. We were both astonished to discover that the bunny was gone. Apparently, the rabbit was playing dead and escaped during our brief indoor em-bell-ishment.

I was searching the nearby bushes when I noticed Cole zip straight to the barn and slip under a large sliding door. The barn has been vacant for many years, so I had to unchain the door and push against its rusty tracks to get inside. I found Cole crouching under an old wagon. By the looks of the straw tunnels on the floor, I could tell where the rabbits were nesting. While I ran around the wagon unsuccessfully trying to snag Cole, he trotted over to the far corner of the barn. Suddenly, we both heard a "ssss-sssssss-sssss", the distinct rattlesnake rattle. Cole jumped back. I threw him out of the barn and then crept over to see if I could spot the rattlesnake. At some point in the past, someone covered the dirt floor of the barn with loose plywood boards which over the years got covered with straw, manure and miscellaneous discarded farm implements. Lots of places to hide. Kinda creepy. Although I could still hear the rattling, I could not see the rattler and I wasn't willing to investigate any closer. I closed up the barn and put boards in front of the larger cracks under the door so that Cole could not get back inside.

Last year, I learned to make early morning rounds of the farmyard on a daily basis. Most evenings before dark, I repeated the rounds, and on weekends, I checked more frequently. This gave me a chance to watch the weather, monitor the thistles warfare, and detect wildlife patterns. I became familiar with the locations where snakes most frequently sunbathed on warm days: the southwest corner of the barn by the back door in the midmorning, and the east side of the barn by the hose in the late afternoon. When the sunning snakes happened to be rattlesnakes, usually small buggers, I captured and moved them far away from the farmyard. I figure it is better to monitor, catch and move a rattlesnake than ignore it and later be unpleasantly surprised.

A few days later, I noticed the sun shining on the back of the barn and figured it was good sun-bathing weather.

First, I saw this:
Then I saw this:
With about six inches of its body laying outside the barn , I could tell this was a northern Pacific rattlesnake (Crotalus viridis oreganus) by the triangular shape of its head and the vertical slit of its pupils. I couldn't tell its overall length or see the rattles, but the span of the head and girth of the body looked larger than most rattlesnakes that I had seen around the barn. It was draped behind a pipe with its body arranged between sun and shade to soak up heat without overexposing itself. I guessed this was cautious behavior of a snake recently coming out of hibernation. I slipped over to the garage to grab my gloves, net, snake tongs and courage. My technique is to slowly place the net in front of the snake - they usually don't move - and then with the tongs snag the snake midbody and toss it into the net. With the pipe in the way, I didn't get a good grip on this rattler on the first try. With much indignant rattling, the snake slipped back into the barn.

I ran around to the other side of the barn, slid open the heavy door and peeked in. It was still rattling furiously and its head and 8 inches of its body were sticking out of a lumber pile at a stiff 45 degree angle. It was watching me watching it. As I approached the lumber pile, it retreated between the boards. I tried to wedge the snake tongs into the gaps between the boards but was unable to get any purchase as I saw coil after coil slip back into the pile. Once again, I closed up the barn and warned the cat to stay away.

Then the April mini-heatwave arrived. On a warm Saturday, I noticed the backside of the barn was bathed in sunlight and I cautiously checked the southwest corner. This time I found the rattler with its entire body just outside the back barn door. I went through my gotta-catch-a-rattler routine: put the curious kids and pets inside, put on heavy leather gloves and boots, gather net and tongs, and take a deep breath.

I successfully captured the rattler although it was tricky for a few seconds because I had to maneuver its body around the pipe to drop it into the net. It was mad and rattling fast and faster. With the snake safely restrained in the deep net, I took a few moments to scream off the tension in the backyard - nice thing about the country, you don't have to worry about nearby neighbors wondering what the heck you are doing.

To get a photo without getting too close, I propped the net over a garbage can and climbed a ladder to shoot from above. The snake was too frisky to relocate on that day, so I dropped it into a pillowcase, tied off the top, and stored it in a locking-top trashcan in a cool part of the garage. Snakes eat infrequently and rarely drink water, so they keep well in a dark, cool place for several days. Just make sure you let your housemates know the plan.

The release of the rattler - coming soon as Snake Weather - Part 2.

Sunday, April 19, 2009

Not Hollywood

This is California.
--- upper pasture at Dipper Ranch ---

This is California.
--- Coyote Ridge east of Morgan Hill ---

--- Anna's hummingbird visiting barberry ---
Real California is not Hollywood. Real California is not Disneyland.

In real California, there are conifer forests, oak woodlands, chaparral, grasslands, deserts, mountains, islands, rivers, bays, ponds, and all the plants, animals, rocks and clouds that come with them.

Pacific Ocean on one side
Sierra Nevada Mountains on the other
diverse natural wonderland

The springtime wildflower bloom has started and the upper pastures where the cattle were grazing on the Dipper Ranch in January and February look especially colorful. Grassland wildflowers currently blooming on the Dipper Ranch are California poppy, popcorn flower, lupine, fiddleneck, red maids, owls clover, blue-eyed grass, purple sanicle, scarlet pimpernel, buttercup, field madder and checkermallow.

One of the two fabulous botanists shown in the first photo above, showed me a game with California poppies she learned as a little girl. I noticed last week that she still plays it. This game is illustrated below along with some websites that have photographs of California wildflowers and and other websites that link to good wildflower hiking spots.

The Natural Resources Database - has plant and animal lists for over 200 open space and nature preserves in the greater San Francisco Bay Area. You can create a simple or fancy list, search, and link to websites with more information such as photos.

Carol Leigh's California Wildflower Hotsheet
- Hikers (mostly photographers) enter dates and places they have recently seen wildflowers with lists. In the spring, someone is usually posting new information every few days.

CalPhotos - over 200,000 searchable photos of plants, animals, landscapes and cultural features. And its more technical companion, CalFlora.

Places that often have good spring wildflower hikes in the Santa Cruz Mountains and nearby areas (click underlined title to automatically get linked to website with more details):

  • Edgewood Park and Natural Preserve - serpentine grasslands make for colorful and unusual wildflowers. Frequent docent lead hikes. Website has flower ID.
  • Russian Ridge Open Space Preserve - hike to Borel Hill for great views and wildflower fields, especially in wet years after prescribed burns.
  • Sierra Azul Open Space Preserve - from the parking lot on Hicks Road, take Woods Trail and Barlow Road to Bald Mountain which weave between sunny grasslands, shady forests and rocky trailsides to provide lots of variety.
  • Almaden Quicksilver County Park - Try the trails off the Mockingbird Hill entrance especially early in the spring.
  • Coyote Ridge - serpentine grasslands with rare butterfly and views to the Hamilton Range, guided hikes only - check website.

A little further out:
Go outside and play. Happy Earth Day.

And for my co-hikers today at Los Trancos Open Space Preserve, here is a list of the wildflowers we saw. In light of all the things I have said about common names, I still used them below but made sure they are the ones also used in the Natural Resources Database so you can check that site for the genus-species name and link to photographs.

purple sanicle
common sheep sorrel
blue field madder
white-stemmed storksbill
English plantain
purple needlegrass
California poppy
scarlet pimpernel
bicolor linanthus (thousands of these teeny flowers!)
California buttercup
California goldfields
Owl's-clover (purple)
annual lupine
sheep parsnip
Pacific sanicle
short-spurred plectritis
checker mallow
California blackberry
blue witch
blue dicks

Saturday, April 18, 2009

Teachers with Two Legs

Yesterday, I briefly met Dr. Robert C. and Rose Stebbins. Dr. Stebbins is 93 years old, an author, Emeritus Professor and expert on reptiles and amphibians of the western United States. For many years, I have used his various field guides and wondered about the man behind this specialized body of work. His most recently published book, Western Reptiles and Amphibians, 3rd Edition, is part of the Peterson Field Guides. The species illustrated in the 55 color plates are reproductions of his hundreds of paintings from live animals, and they truly bring forth the colors and striking beauty of these varied creatures. His species descriptions are organized, precise, and I am slowly learning to respect their density as I repeatedly refer to them while observing snake, frog, toad, or newt species through the seasons on the Dipper Ranch.

This week, the manager of our open space district mentioned that Dr. Stebbins would be visiting our office the next day and offered to introduce me. This is the only time I have ever been thankful to be stuck in the office on a spring day instead of having field work. I was excited and nervous, and remembered being a little girl bugging my dad with questions about flowers. That night, I fretted about selecting only a few questions to ask Dr. Stebbins out of the many mysteries I ponder at the Dipper Ranch. Late in the night, I finally decided I was going to ask him:
  • Do the eggs and aquatic larvae of coast range newts contain the neurotoxins that are found in the adult newts?
  • How long after hatching do the newt larvae transform into their terrestrial phase, first summer or second summer?
If there was time, I was going to ask him my current burning question:
  • Why do Pacific treefrog tadpoles have camouflage coloration, whereas western toad tadpoles are dark black and not camouflaged? Is it because the toad tadpoles already contain the foul-tasting substances found in skin glands of the adult toads and don't need to hide?
Dr. Stebbins was wearing a dandy field hat as he relaxed in the leather executive chair while his family and friends discussed where to go hiking. He was charming and patiently listened as I babbled on about how I used to be scared of snakes and now I find them fascinating. He very graciously signed my copy of his field guide.

While speaking to his wife, Rose, I discovered that she is the artist who created a beautiful and accurate needlepoint rendition of a dragonfly hanging in this manager's office. I have spent many calming moments admiring this dragonfly and pretending that I was outside, while waiting for executive decrees and trying to grind through the boring administrative tasks it takes to protect natural lands.

I am embarrassed to admit that I didn't build up the courage to ask Dr. Stebbins any of my questions. So silly of me. I promise that the next time I am provided with such a unique opportunity, I will ask at least one question. I am grateful to have briefly met him. I am inspired by his work and how many people he has taught to observe the natural world around us.

<--- My dad and son discussing the physics of old farm equipment on the Dipper Ranch. ---

Teachers and education have been important in my life. My parents are both retired university science professors, and I have a brother, sister and niece who are teachers. I turn 50 years old in a few weeks, and my recent move to the Dipper Ranch has been a big change in my life. I am so grateful to have this opportunity to observe nature up close day after day. I am bursting with observations and questions and, thanks to the encouragement of my sister-teacher, I started the Dipper Blog 6 months ago to share these stories with more people.

Even after studying and working in the biological field for 30 years, every time I write a blog entry, I need to spend time researching questions and learning more about the natural world around me. I am also struggling to learn effective ways to transition from traditional books and classroom lectures to today's blog format as a way to share natural history. Thanks to Dr. and Mrs. Stebbins, my family, associates and all the teachers out there for your inspiration and I promise to stay an eager student for my next 50 years.

Thursday, April 9, 2009

A Snake of Many Colors

The first snake spotted on the Dipper Ranch in 2009 was a gartersnake. What kind of gartersnake? That's a colorful tale.

It's been warmer. The daytime temperatures have been in the 60's, although sometimes it has been in the low 40's at night. Fence lizards appear on their favorite sunning rocks and startle you by zipping around every bush and rustling in the winter's carpet of brown leaves. You suddenly remember - we've been reptile-less for the last few months. So, when are the snakes going to appear?

Reptiles are basically immobilized in cold temperatures. Rattlesnakes, for example, are unable to move when temperatures are 46 degrees F or less (Klauber). Even in the mild winters of the central California coast, no amount of sunbathing or lizard push-ups can help the reptiles efficiently recalibrate their ectothermic bodies (casually referred to as cold-blooded). Instead, reptiles hibernate during the cold winter months, usually underground where the temperature extremes are somewhat insulated by the great mass of surrounding earth.

Snakes may hole up alone or with other snakes of same or different species. When the warmer weather arrives, they may spend several days sunning at the entrance of their winter den before heading off to find the spring crop of baby rodents, rabbits, birds and insects.

With this coldblooded cycle in mind, I started checking the ranch springboxes (aka the snake-o-meters) more frequently. On the first Sunday in April, I found this lovely 23-inch long gartersnake in the middle of the main springbox. To retrieve it from the 5-foot depth of the vault, I had to belly flop onto the concrete sill and flip it with the Gentle Giant snake tongs into the muslin net I was holding in front of its nose with the other hand.

We have 3 to 4 species of gartersnakes in the Santa Cruz Mountains. They're mediumllly (when writing about snakes, you are allowed to use words with extra 'l's in them) slender snakes with long, usually colorful stripes down the length of their bodies.

A hint about gartersnake identification: there are about a zilllllion gartersnakes in the world. There are disagreements among herpetologists about the number of gartersnake species, subspecies and just plain regional variations, and how to identify, classify and name them, and you get the feeling these folks spend a lot of time gazing at these colorful snakes mesmerizing themselves.

The Sunday gartersnake came with these clues. It had a yellow stripe down its back, and then further down its side, a black stripe that checkered into a red stripe, and then another black stripe. The snake had a light blue-greenish belly with orange blotches and a dark brown color on the top of its head. And 8 upper labials (scales above the jaw) on each side. So, I think it is a coast gartersnake in the western terrestrial gartersnake group. I should have checked the shape of a pair of scales under the chin, but while holding the snake in one hand and camera in the other, I couldn't get the snake to look up for me. Something about examining snakes, I always feel like I need another hand even though they get by with none.

This snake had an irregular red blotch across its dorsal yellow stripe 10 inches back from its nose. This might be a prior injury. I photographed and measured this irregularity as a possible way to identify the snake if it shows up again.

Two other gartersnake subspecies occur in the Santa Cruz Mountains that look somewhat like the coast gartersnake, but I have not seen them yet on the Dipper Ranch. The San Francisco gartersnake only occurs in the San Francisco peninsula, is listed on the Federal and California endangered species lists, and has been found on nearby properties. Compared to the coast gartersnake, the San Francisco gartersnake has a bright red head, its dorsal stripe is usually turquoise instead of yellow, and it has 7 upper labials. Closely related to the later is the California red-sided gartersnake, whose red sides are more spotty than striped, and it doesn't have the brilliant turquoise.

If this seems likes a whirl of colors, it is confusing, so either enjoy the wondrous mysteries of nature or stop reading the Dipper Blog right now and go to the California Herps website. This excellent website has many photos, patient descriptions, audio and video clips, and the contributions are made, reviewed and updated by many western experts. As a botanist, I am constantly awed by the valuable and attractive information at this herptofauna (reptiles and amphibians) site.

Gartersnakes are generally found in or near water, so I took Sunday's beauty to the nearby Woods Pond where I still hear treefrogs, a tasty spring meal. When I first released this coast gartersnake, it practiced a snake yoga pose known as the Hydee-Head wherein you tuck your head under several coils in order to regain your composure. This snake had an interesting twist to the pose by curling and raising its tail tip about an inch off the ground. Perhaps this was a decoy so that any predators would not initially strike its more vulnerable core body, or perhaps with 23 inches of body to arrange, it just forgot about the tip.

After 5 minutes of the Hydee-Head pose, the snake lifted its head for several more minutes of contemplation. Then it uncoiled itself and stretched out towards the pond. As you can see in the last few photos, its stripes, which were so bright and lovely against the sky in my gloved hands, actually blend quite well when woven among the pond vegetation, mud and water.

--- Where did that snake go? ---
(Give up? It's in the center of the photo. See enlargement of photo below.)

See also:
coast gartersnake (Thamnophis elegans terrestris)
San Francisco gartersnake (Thamnophis sirtalis tetrataenia)
California red-sided gartersnake (Thamnophis sirtalis infernalis)

Laurence M. Klauber, Rattlesnakes, Their Habits, Life Histories, & Influence on Mankind, abridged edition, University of California Press, 1982.
Robert C. Stebbins, Western Reptiles and Amphibians, 2003.

Tuesday, April 7, 2009

Tadpoles Compared

Here's a California toad guarding his hole from the foreclosure agents. You can tell he is a toad by the yellowish line down his back. And the warts. But how do you tell a toad tadpole? They're black commas.

Let's update the progress of the toad eggs. We originally mistook them as tangled shoestrings in the Newt Pond on March 18th. California toad eggs are black dots laid inside long, double-walled, clear jelly tubes. On March 22, we noticed the tubes had started to break apart even though the eggs were still roundish and the embryos were not developed. Toad tadpoles hatch out in 5 or 6 days by busting through the jelly tube.

<--- busted toad tubes by David Tharp ---

I am not sure why these tubes were already broken apart. My guesses are: the Newt Pond is high on a ridge, and sometimes the wind creates a fetch that agitates the shallow water and may have broken up the tubes prematurely. Curiously, we saw many tiny, white mite-like critters clustered on the jelly tubes and maybe they were breaking them up. Or maybe the hatching is spread apart by several days and some tadpoles busted out early, loosening their brethren eggs. Good thing the toads hatch out in just a few days, otherwise, I would probably come up with more theories.

<--- 'mites' on toad tubes by David Tharp ---

In any event, the hatching seemed successfully, as by April 5th, thousands of toad tadpoles were massing along the edges of the pond. The toad tadpoles start out about 6 mm long and are dark black, so black you can't make out their features.

Compare this to the Pacific treefrog tadpoles that hatch in 6 days, quickly grow to 1 cm, develop enormous tummies and are camouflaged with dark olive backs marked by black dots and a coppery underside.

<--- treefrog tadpole on left, toad tadpole on right ---

I am not sure why the toad tadpoles are so dark and obvious and the treefrog tadpoles have cryptic coloring. I carefully watched adult newts nosing about the pond vegetation in a hunting pattern and they did not snap at the black commas as they wiggled by. Adult toads have toxic, foul-tasting substances (Pickwell) in their "warts" (why dogs usually spit out toads), but I don't know if the tadpoles are so equipped. Pickwell notes that predacious water insects capture and suck the fluids from frog and toad tadpoles.

Meanwhile, the newt eggs have been developing into twitching knife-like larvae and carving out of their individual eggs and then the outer casing. A number of newt egg clusters were washed up on shore on the windy day I last visited the Newt Pond. As I tossed them back into the pond, I noticed several newtlets pop out of the floating cluster and swim away. I cheerfully shouted, "I birthed them!" and the coyote hunting rodents in the nearby meadow looked my way.

<--- newt larvae about to bust out ---

Toad and frog tadpoles are herbivores and spend their days scraping up algae and decaying matter from rocks and the pond bottom with sucking mouths and tiny teeth. Newts are carnivorous all their life, so their larvae are devouring small pond critters. I rarely see newtlets in the ponds; as carnivores, maybe they lurk in the shadows.

The toad tadpoles will metamorphize in about 8 weeks from egg laying or mid-May. Will the water in the Newt Pond last that long? It rained today, so maybe. They hop out of the pond as tiny toads 6 mm from snout to tail end, and sometimes they still have a bit of tadpole tail they carry around for awhile. The treefrog tadpoles take about 12 weeks to metamophize, so that would be mid-June. Hmm, not sure if the Newt Pond is going to last that long, but treefrog eggs in the deeper Plum and Mallard Ponds will certainly have enough water to get to hopping stage.

I rarely see tadpoles of the California red-legged frog. They are larger (up to 7.5 cm long), dark brown or yellowish above, shiny pink below with white spots in a line along each side (Stebbins). From above, their eyes are closer to the centerline of the head and not along the outer edges like the treefrog. Both the red-legged frog tadpoles and the newtlets can spend over a year before they metamorphize, so they need longer-lasting ponds.

Thanks to my pond companions who provided some of these great photos and co-speculate on the mysteries of shoestrings and busted jellies. We are going to have a toad party in May if the Newt Pond lasts that long.

<---can you find the hidden treefrog tadpole?---

See also:
California toad, Bufo boreas halophilus
Pacific treefrog, Pseudacris regilla
Coast range newt, Taricha torosa torosa
California red-legged frog, Rana draytonii

Gayle Pickwell, Amphibians & Reptiles of the Pacific States, Dover Publications, 1972.
Robert C. Stebbins, Western Reptiles and Amphibians, 2003.