Thursday, January 1, 2015

The Bucket Theory

Preserved specimen of California newt at the Museum of Vertebrate Zoology, University of California, Berkeley.
This is specimen MVZ:Herp:8101.
Photograph from the Museum's Collections Database at   
Late at night I was pouring through field guides, scientific publications, and online catalogues of museum specimens, but they didn't give me answers as to how red-bellied newts arrived in the Stevens Creek watershed. The little creatures we found were so far out of their reported range, if I was going to get any sleep, I needed the help of experts. So I started calling around.

The bumbling phone calls usually went like this:
I introduced myself as a biologist who managed open space land in the Santa Cruz Mountains, the coastal mountain range between San Francisco and San Jose. 
I took a deep breath and then rushed into saying we found something unusual - red-bellied newts 80 miles out of their known range, and not just one red-bellied newt but what looked like a population with several age classes. 
Long silence on the other end of the phone. 
I acknowledged that this seemed like a mistake, but I had photographs and I had seen them myself. 
Clearing of throat on the other end of the phone, "Are you sure?"
And so on. It was hard to get anyone to believe us.

We started by calling the herpetofauna consultants we usually work with, which means they were experts about the rare amphibians and reptiles known to occur on the preserves - California red-legged frog and San Francisco gartersnake - and likewise quite familiar with the the California and rough-skinned newt species common in the San Francisco Bay region. But when we asked about any sightings of red-bellied newts (rbns) in Santa Clara or San Mateo Counties, they hesitated.

When you say rare red amphibian in the Santa Cruz Mountains, people usually assume you mean the California red-legged frog officially designated as threatened   
Even when we emailed them photos of the red-bellied newts in the Stevens Creek watershed, one could hear waves of doubt in their tepid response. They didn't exactly say we were mistaken, but still, red-bellied newts in the Santa Cruz Mountains seemed crazy so they would refer us to someone else.

And then there is the San Francisco gartersnake, an endangered snake that is endemic to the Santa Cruz Mountains and has red stripes and a bright red head.   
Desperate to confirm this unusual situation and determine if we needed to take any protective action, I made a cold call to a herpetologist at a San Francisco research institution who, according to my late-night internet research, had studied the Taricha genus of salamanders. Someone who didn't know me and probably had never heard of the Midpeninsula Regional Open Space District, and he was incredulous. He said amateurs often mix up salamanders but he reluctantly agreed to look at our photos. I took down his email address, picked our best three photos of rbns in the Stevens Creek watershed, and sent them speedily on their way. A few minutes later he called me back and suggested I was possibly faking the photos. Ouch, I was in way over my head.

I emailed Gary Nafis, the developer of California Herps, a website Guide to the Amphibians and Reptiles of California which, in addition to providing descriptions and range maps of over 200 species and subspecies of California reptiles and amphibians, also puts a special emphasis on photos illustrating regional differences or unusual forms of the animals. As with the others, he could not confirm red-bellied newts in Santa Clara County but he encouraged us to continue recording our sightings with dates, locations and photos.

Crazy people looking for newts   
On rainy weekends, I would organize a loose group of friends, neighbors, rangers, biologists and docents and we would hike around the Stevens Creek watershed. It was a hit-and-miss affair and not everyone liked to hike on rainy days. If they didn't see the rbns themselves, some of my companions would fidget, gloomy with doubt on the long crawl out of the forested canyon. And when someone did see one, even if it was the first or fifth time, they would beam with happiness and excitement. We hiked on, sometimes seeing them and sometimes not, but recording any information we could to detect how many rbns there were, when they moved and where they went.

Just another drippy day on the trail   
In the rainy months of December 2009 and January and February 2010, we scoured the Stevens Creek watershed eight times and saw a total of a few dozen red-bellied newts while on some days we saw one hundred or more California newts. In the hours we hiked up and down the hills and on all those phone calls, The Bucket Theory kept coming up - maybe someone had collected a bucket of red-bellied newts in northern California and dumped them in Stevens Creek. We speculated that the introduced newts regrouped, found suitable aquatic and terrestrial habitat in their new home, and went forth and multiplied.

After all, if this was a natural population of red-bellied newts long ago separated from the larger population in northern California, it didn't make sense that no-one had previously noticed them in the Stevens Creek watershed. In our surveys of the past nine months, we were occasionally seeing the red-bellied newts on trails. These trails were in parks that had been open for public recreation for decades. Surely some of the thousands of hikers visiting these parks every year would have also seen and recognized red-bellied newts as distinct from the usual orange newts. Furthermore, the San Francisco Bay area is home to Stanford University, San Jose State University, San Francisco State University, University of California - Berkeley, Hayward State University, University of California - Santa Cruz and numerous community colleges, most of which have biology programs.

Surely some instructor, class, or salamander-enthusiast would have stumbled onto this population in the last 50 or so years.

Some of our early photos of squirming salamanders in the dark forests were blurry, but they certainly were not fakes.   
A check of the amphibian specimens at the California Academy of Sciences in San Francisco and the Museum of Vertebrate Zoology in Berkeley didn't yield any clues. Specimens of the other two Taricha salamander species collected from the Santa Cruz Mountains have been floating in bottles of preservatives at the museums at least since 1906. But the museum specimens of red-bellied newts were all from far north of the Santa Cruz Mountains and not collected until 1935.

California newts are common in MROSD preserves and can congregate in large numbers in ponds where they and their large egg masses are readily visible. Hunting for newts during their seasonal land migration or in creeks is not as easy.  
Simultaneously, I was checking unpublished material. In 1999 and 2000, herpetologists Rich Seymour and Mike Westphal surveyed 38 streams, 35 ponds, and 114 terrestrial locations across the 46,000 acres and 23 preserves that made up the Midpeninsula Regional Open Space District at that time (Seymour and Westphal, 2001). Their surveys included ponds and the main stem of upper Stevens Creek in the Monte Bello Open Space Preserve. They not only visited suitable wet habitat for amphibians during the day, but also returned to prime areas at night to make sure they were getting a complete assessment including driving roads on rainy nights to detect dispersing amphibians and roadkills. This report became a fundamental resource for our agency to determine the locations and sizes of populations of the threatened California red-legged frog in the preserves. Seymour and Westphal observed many salamander species, and noted that rough-skinned newts and California newts were common in the preserves, however, at no time did they mention seeing any red-bellied newts. I called Rich Seymour to share the 2009 red-bellied newt sightings in Monte Bello Open Space Preserve and he was astonished.

There was one other resource I pulled off my bookshelf, a 1947 book which gives a good picture of the natural history of herpetofauna in the Santa Cruz Mountains when they were still rural with cattle ranches and second-growth forests before the influx of roads and houses. In Amphibians and Reptiles of the Pacific States, Dr. Gayle Pickwell, a professor of Zoology at San Jose State College (now San Jose State University) in the 1920s and 30s, shares many first-hand accounts of animals in their natural habitat. And since San Jose is located at the foot of the Santa Cruz Mountains, we can assume he knew the salamanders there very well. Indeed, here is his description of the salamander we now call the California newt (Taricha torosa)*:
Our study of Triturus torosus, the Pacific Coast Newt, took us on one occasion to some little pools in the Santa Cruz Mountains . . . this was January 18 . . . Our every footstep along the margin of the pond was accompanied by a swish of swimming tails, a swirl - and there, in the clear water, we could see brown, four-legged Salamanders swimming away.
In the identification keys at the back of the book, Dr. Pickwell describes the red-bellied newt as "Iris of eye all black . . . ventral surface tomato-red with red coming around on dorsal surface of digits" and then he goes on to say "seems to be confined to the coast range Redwood belt, southward into Sonoma County and probably northward to Del Norte County." Again, indicating that no-one had reported red-bellied newts in the Santa Cruz Mountains in the mid-twentieth century.

At one point after pouring over aerials with elevation lines, little red X marks and GPS points of our 21st-century rbn sightings, I spotted a nearby private property with ponds and several tributaries of Stevens Creek and convinced myself that was where the rbns were coming from. And I knew who lived there - one of our former rangers had leased the property for many years. He was just the type of guy to "improve" the property with more wildlife.

I approached both him and his wife and queried, "Did you release red-bellied newts on this property?"

"What's a red-bellied newt?" they responded in confusion.

I presented photos and stabbed my finger at an aerial of the property and accused them again, but they maintained they had never seen a red-bellied newt and I believed them. I had to accept that the mystery of the red-bellied newt was not going to be easily solved.

And the thing is, it's just not common for newts to adapt to a new area probably because they have such a strong inclination to return to their natal stream. In the lack of any other evidence, The Bucket Theory wasn't holding up either.

It occurred to me to consider that Dr. Victor Twitty of Stanford University, the scientist who had originally discovered red-bellied newts in northern California and studied them for thirty-two years, could have possibly released newts in Stevens Creek. In the 1970's, Stanford University owned a track of land in the upper Stevens Creek watershed with several tributaries, springs and vernal pools around Black Mountain. I started reading Dr. Twitty's experiments on the homing behavior of red-bellied newts, but nowhere in his papers could I find any suggestion that he found or released rbns in the hills above Stanford.

Finally one day, I flashed a photo of the red-bellied newt past the Undercover Naturalist during a brief conversation in the lobby of our main office. He asked for more photos. I sent him photos, survey dates and numbers of red-bellied newts seen. He believed us. He called his associates at the Museum of Vertebrate Zoology at the University of California - Berkeley. A few days later, he found me and said, "Call Dave Wake at the MVZ. He's interested."

So I did. I went through my spiel again, dates, distinguishing traits, the oddity of it all. Dr. Wake listened patiently and had obviously looked at the photographs. I charged right in and invited him to come out to the Stevens Creek watershed to see the newts. He agreed.

"Yikes," I thought, "we've only seen 28 of these unusual newts over the past nine months. What if they don't show up on our field day?" But a date for the expedition had been set, and rain or shine we were going.

A page from the Catalogue of the Department of Herpetology, California Academy of Sciences.
CAS 122766 records a preserved specimen of Taricha rivularis collected in Mendocino County by V.C. Twitty in 1935.     
To be continued as Commander Salamander.

This post is the sixth in a series on the discovery of red-bellied newts in the Santa Cruz Mountains of California. To start at the beginning of the series go to Mystery of the Red-Bellied Newt.

*The three Taricha newts of interest in this story have been given various scientific and common names through the decades (e.g. Triturus or Notophthalmus genus), and sometimes have been recognized as the same or separate species or subspecies. I have generally used their currently accepted nomenclature and where necessary such as quoting historical publications, provided the current names in addition to older names.

California Academy of Sciences, Herpetology Collection, accessed December 30, 2014.

Museum of Vertebrate Zoology at the University of California, Berkeley, Herpetological Collection, accessed December 30, 2014.

Seymour, Rich and Mike Westphal, 2001, Results of a One-Year Survey for Amphibians on Lands Managed by the Midpeninsula Regional Open Space District in the Santa Cruz Mountains of California.

Gayle Pickwell, 1972, Amphibians and Reptiles of the Pacific States, Dover Publications, New York. This edition is the original 1947 publication with a new Foreword and Table of Changes in Nomenclature prepared by his son, George V. Pickwell who states in the Foreword, "My father's original intent was not just the presentation of a handbook for identification of Pacific Coast amphibian and reptiles . . but rather the presentation of the fascinating life stories of these animals, especially as he had himself observed them in the wild through long hours and days of field study." Dr. Gayle Pickwell was one of the co-founders in 1931 of the West Coast School of Nature Study at San Jose State College which included many field projects at natural areas throughout the state including Big Basin State Park, Asilomar State Park, and especially Death Valley National Park. This program continues today as the Field Studies in Nature every summer at San Jose State University. I'm sharing this background info on Dr. Pickwell because I know some of the Dipper Ranch readers are enjoying these field courses even today.

Rough-skinned newt, Taricha granulosa
California newt, Taricha torosa
Red-bellied newt, Taricha rivularis
California red-legged frog, Rana draytonii
San Francisco gartersnake, Thamnophis sirtalis tetrataenia

1 comment:

  1. This is an interesting series of posts, Cindy! The natural history mystery is balanced nicely with the scepticism and assumptions of humans. Most enjoyable.


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