Undercovert Identification

The striking black-and-white wing pattern of a Willet in flight, photo by Mike Baird

Flash! Upon takeoff, the drab, grey, unnoticed Willet, Catoptrophorus semipalmatus, becomes one of the sharpest dressers around. Black-and-white wings bear a striking, vibrant pattern as the birds move down marsh channels to flight calls of clay-dr-dr. A few Marbled Godwits are usually along for the ride; they keep perfect pace with the willet flock despite being larger shorebirds with different wingspans. Look for their long, straight,  pink bills, ends dipped in black, a godwit signature.

Marbled Godwit with black-dipped beak, photo by Dick Daniels

Winter finds the Western Willet subspecies along Central California coasts, mudflats, and salt marshes. In tidal areas, Willets nab crustaceans, key prey, by sight. But the willet has other feeding strategies too, for example, probing deeply into mud for worms and small mollusks, at times feeding with several inches of water lapping at its grey legs, black and white hidden under dull gray. It's the dull secondary coverts, feathers central in the wings, that conceal the willet's striking wing patterns when the wings are folded.

During breeding season, the Western Willet displays barred patterning across its chest and sides. While shorebirds generally migrate to marshes in western prairies or north into Canada and Alaska, some Western Willets stay further south, many in Great Basin grasslands and deserts just east of the Sierra Nevada. Note that this habitat is quite different from that of the Eastern Willet subspecies, which nests in coastal Atlantic salt marshes.

When not in flight,Willets have a drab appearance, photo by Bruce Tuten

Interestingly, the Western Willet subspecies flies from summer inland breeding areas to wintering grounds both coasts. Meanwhile the slightly smaller Eastern Willet subspecies, rather than remaining on the East Coast where it nests, departs North America in fall for wintering grounds thousands of miles to the south.–Anne M. Rosenthal

Sibley, David Allen. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York.

Elphick, Chris; Dunning, Jr., John B., and Sibley, David Allen. 2001. The Sibley Guide to Bird Life & Behavior. Alfred A. Knopf, New York.

as well as Personal Observations

An Unlikely Outcome

Can you find two salamanders in this picture?

Not becoming a meal is the basis for many salamander adaptations, physical, chemical, and behavioral. The California Slender Salamander, Batrachoseps attenuatus, is no exception: it employs a mix so potent that a snake vs salamander encounter resulted in a surprising outcome.

As a starting point, their dark grey-black coloration combined with a dorsal stripe in one of various leaf-litter shades makes these salamanders almost invisible at first glance. Not surprisingly, like many animals with cryptic coloration, their first line of defense is to remain still.

Escape behaviors noted by Stebbins in the 1972 edition of California Amphibians and Reptiles include flipping about violently or wriggling away rapidly with movement similar to that of a snake. A seized tail may break off and thrash about, mentions Stebbins, sidetracking a would-be predator. An account by Robert W. Hansen and David B. Wake on AmphibiaWeb mentions flipping behavior that can propel the salamander 10 to 20 cm away, described in a 1974 Herpetologica paper by Brodie et al.

Predators avoided in this fashion include snakes, larger salamanders, birds, and mice. But what happens if a snake gulps a California Slender Salamander head first?

In a set of experiments conducted at the University of Chicago by zoologist Stevan J. Arnold, now at Oregon State University, Arnold observed salamander defenses against garter snakes. A photo included in his 1982 Copeia paper documents a garter snake seizing a California Slender Salamander by the head. The next photograph shows the salamander's tail looped around the snake's neck, evidently the result of thrashing on the part of the salamander, which led to the salamander's release. Unfortunately for the snake, during its salamander encounter, the snake was coated with gluey secretions from the salamander's skin. A third photo shows the snake stuck to itself in a coiled position with its mouth glued open. Score: Salamander-1, Snake-0.–Anne M. Rosenthal

Close-up view of the two salamanders in the top photo

amphibiaweb.org

Arnold, Steven J. 1982. A Quantitative approach to antipredator performance: salamander defense against snake attack. Copeia No. 2: 247-253. 

Stebbins, Robert C. 1972. California Amphibians and Reptiles. University of California Press, Berkeley.

Outstripping a Parasite

Moving a planter from atop a rotting stump revealed a California Slender Salamander

With chytrid fungus infections causing large-scale mortality in many amphibian populations, could the California Slender Salamander (Batrachoseps attenuatus) be at risk?  Rolling back downed wood and closely examining the ground beneath often reveals these salamanders coiled and motionless. (Careful replacement of the wood is essential in preserving the ecological communities that are uncovered.)

Inhabitants of chaparral, oak woodlands, and forests, as well as backyards and lots with leaf litter and cover objects, California Slender Salamanders are found throughout the San Francisco Bay Area as far south as Monterey Bay, north along the coast into Southern Oregon, as well as in scattered locations inland. Despite the current range and density of these salamanders, could a chytrid fungus outbreak substantially lower populations, or has this species developed a way of coping with a deleterious infectious organism?

Sara Weinstein, currently a PhD student in the Department of Ecology, Evolution, and Marine Biology at the University of California, Santa Barbara, studied chytrid fungus infection of the California Slender Salamander for her undergraduate honors thesis at the University of California, Berkeley. The work was published in the journal Copeia in 2009.

Through examination of preserved specimens collected earlier, Weinstein determined that amphibian chytrid fungus, Batrachochytrium dendrobatidis, had infected the California Slender Salamander since at least 1973. (Previous to her study, the earliest evidence for amphibian chytrid infection in California was a mountain yellow-legged frog collected in 1975.)

In the case of the California Slender Salamander, amphibian numbers seem stable despite clear evidence of sporadic chytrid disease outbreaks. Chytrid-related mortality of these salamanders occurs mainly during the latter part of the wet season and the months immediately following, from approximately February through May. In contrast, during dry summer conditions that limit fungal growth, it appears that California Slender Salamanders are able to rid themselves of infection through excessive skin shedding and tail loss, essentially removing the parasite faster than it can reproduce.-Anne M. Rosenthal

Stebbins, Robert C. 2003. A Field Guide to Western Reptiles and Amphibians, Third Edition. Houghton Mifflin Company, Boston.

Weinstein, Sara B. 2009. An aquatic disease on a terrestrial salamander: individual and population level effects of the amphibian chytrid fungus, Batrachochytrium dendrobatis, on Batrachoseps attenuatus (Plethodontidae). Copeia No. 4: 653-660.

Seasonal Rhythms of Slender Salamanders

Elongate slender salamanders surface during the rainy season.

Wet weather ambles are the rule for California Sender Salamanders (Batrochoseps attenuatus), one of twenty or so slender salamander species on the Pacific Coast. Like other members of the lungless salamander family, they breathe through skin that must remain moist for oxygen to pass through. In wet coastal areas, California Slender Salamanders may be active year around, but in dryer parts of their range, they retreat underground over the hot, rainless months. 

During the rainy season, California Slender Salamanders are daytime homebodies, remaining under the board, rock, log or other cover object beneath which they reside. On warm, rainy nights, they foray out, but generally within just a few meters of their abodes.

An exception is females heavy with eggs, which may wander farther–during late fall and early winter, sexually mature females lay small strings of eggs in communal nests. One nest, found "in a small depression in damp soil beneath a strip of tin at the northwest corner of Cedar and Spruce streets" in Berkeley, California, was described in the 1939 issue of Copeia by Thomas Paul Malin, Jr. The depression contained "small lumps of earth and a little organic material," in contrast to dry surrounding soil. Besides the female in the act of laying a string of eggs, which were attached to each other by small strands of gelatin, there were three other adult females and a total of 74 eggs in the nest.

Malin measured the eggs to be 6 mm, including a gelatinous capsule, with the "egg proper" 4 mm. His investigations of California Slender Salamanders from the San Francisco Bay Area showed that egg formation began in the ovaries during May, with females carrying an average of about 12 eggs by November, the oviducts "enormously developed...turgid with gelatinous secretions," whereas females taken in December had ovaries with "resting-stage" appearance.

Unlike many salamander species, slender salamanders require neither ponds nor streams for reproduction. Eggs hatch in winter or spring releasing tiny, fully formed salamanders, rather than water-inhabiting tadpoles.

The seasonality of salamander activity and reproduction are reasonably accessible to a sharp observer, but the intricacies of seasonal change within the cells of a salamander are rarely uncovered. A stunning discovery was inclusions of protein crystals within the liver cells of California Slender Salamanders.

Crystal prevalence varied by individual salamander, as well as by season, and indicated high concentrations of protein, possibly a storage form. Note that the crystals are surrounded by membranes of the endoplasmic reticulum where protein synthesis takes place. In the micrograph, these appear as fine wavy lines around the crystals.–Anne M. Rosenthal

Protein crystalline inclusions in California Slender Salamander liver cells. Transmission electron microscopy (TEM) image by Don W. Fawcett.


http://amphibiaweb.org

www.californiaherps.com

Fawcett, Don W. 1981. The Cell. WB Saunders Company. Free web-based copy available: http://www.ascb.org/bioeducate/FawcettTheCell.html

Maslin, Jr., Thomas Paul. 1939. Egg-laying of the slender salamander (Batrachoseps attenuatus). Copeia No. 4: 209-212.

Morey, S. and H. Basey. 1988-1990. California Wildlife Habitat Relationships System, California Slender Salamander. California Department of Fish and Game.

Olson, Deanna H. 2008. Conservation assessment for the California Slender Salamander in Oregon Batrachoseps attenuatus) Version 1.0. U.S.D.A. Forest Service Region 6 and U.S.D.I. Bureau of Land Management Interagency Special Status and Sensitive Species Program.

Stebbins, Robert C. 2003. Western Reptiles and Amphibians, Third Edition. Houghton Mifflin Company, Boston.

Backyard Nature: Slender Salamanders

The legs of slender salamanders are minute, giving them a snake-like appearance.

With their skinny bodies and miniscule legs, slender salamanders (genus Batrachoseps) are often mistaken for small snakes or earthworms. These salamanders are common residents of moist, leaf-strewn ground, hiding under cover objects such as rotting logs, rocks, or planters. Their slim, elongate bodies slip easily into worm holes and termite galleries as they search for meals; slugs, millipedes, mites, roly-pollies, spiders, and various insects round out their diet. Despite the slender salamander's sluggish appearance, its tethered projectile tongue snags prey half a body length away in a fraction of a second.

Garden habitat for slender salamanders: Substantial leaf mulch with flower pots and a planter serving as cover objects.

Restricted to California, except for small areas in Oregon and Baja California, slender salamanders are a fascinating example of "cryptic species." Across their range they appear so similar that scientists originally divided the group into just three species.

However, in the 37 years between the publication of the 1966 first edition of Robert C. Stebbins' authoritative Field Guide to Western Reptiles and Amphibians and the 2003 third edition, scientists discovered that the group comprised twenty distinct species, despite their near-identical appearance.

To investigate the species puzzle, scientists examined DNA found in mitochondria, which are organelles present in complex (eucaryotic) cells, such as those in multicellular organisms like salamanders. Mitochondria house the manufacture of ATP molecules, a chemical currency used by cells for their energy requirements.

Importantly, mitochondria have their own DNA (mtDNA), a tiny set of genes separate from the main genome that is contained in the cell nucleus. Since mitochondria have limited DNA repair mechanisms, mistakes made during DNA replication may not be fixed; over successive generations, mtDNA tends to accumulate changes. If two salamander populations have been isolated from each other for a lengthy period of time, their mtDNA will differ substantially. Therefore, finding multiple mtDNA differences between two populations indicates they have been separated for some time and that speciation may have occurred.

Scientists also look for variation in enzymes, which are proteins that speed up chemical reactions within a cell. Enzymes help cells get things done in a timely manner, facilitating processes such as building cellular structures or dismantling large molecules for their components.

Proteins are composed of amino acid chains; the code for the chains is encrypted in nucleotide bases on strands of DNA. If DNA mutates, the code may specify a different amino acid, slightly changing the protein. When salamander populations are separated from each other, protein differences between them mount over time. This results in enzyme variants termed allozymes, which are coded for by alternate versions of the same gene.

But how are allozymes detected? Since some amino acids carry electrical charge, substituting one amino acid for another can affect the overall electrical charge on a protein. When two different proteins are placed on a gel with a positive electrode at one end and a negative electrode at the other (electrophoresis), the proteins will separate from each other according to charge.

Using both mtDNA and allozyme analysis, Elizabeth L Jockusch, Kay P. Yanev, and David B. Wake studied slender salamander populations in Central California and were able to clearly sort 62 populations of Central California salamanders (from Monterey Bay to Morro Bay) into four new species, work published in 2001 in Herpetological Monographs. They also used slender salamander mtDNA as a molecular clock to estimate how long ago species differentiated from each other, which ranged from several million to well over ten million years ago and generally correlated with geologic events that could have isolated populations, leading to speciation.–Anne M. Rosenthal

Jockusch, Elizabeth L., Yanev, Kay P., and David B. Wake. 2001. Molecular phylogenetic analysis of slender salamanders, genus Batrachoseps (Amphibia: Plethodontidae), from central coastal California with descriptions of four few species. Herpetological Monographs, Vol. 15: 54-99.

Lombard, Eric R. and David B. Wake. 1986. Tongue evolution in the lungless salamanders, Family Plethodontidae. IV. Phylogeny of Plethodontid salamanders and the evolution of feeding dynamics. Systematic Zoology Vol. 35(4):532-551

Stebbins, Robert C., 1966, A Field Guide to Western Reptiles and Amphibians. Houghton Mifflin Company, Boston

Stebbins, Robert C., 2003, Western Reptiles and Amphibians, Third Edition. Houghton Mifflin Company, Boston

AGU 2011 New Imaging for Hydrothermal Vents

Tube worms at Endeavor Hydrothermal Vent Field, northeastern Pacific Ocean. Photo courtesy of NOAA

At the mid-ocean ridges, spreading zones where sea floor is pulled apart by the movement of adjacent tectonic plates in opposite directions, lava from Earth's interior spills into the gash, creating new landscape of oceanic crust. Hot, sulfide-laden fluid courses through subterranean lava pipes, shooting upwards in scorching, chimney-building geysers or percolating through more diffuse vents. And life quickly colonizes the hydrothermal vent fields: bacterial mats look like white paint splashes on a black floor; in the Atlantic, masses of blind shrimp swarm the vents; in the Pacific, giant red-plumed tube worms feed the bacteria they harbor by clustering near sulfide-rich waters.

In fact, throughout the world's oceans, an assortment of unusual invertebrates, often astounding versions of familiar characters like snails, crabs, and lobsters, reside at hydrothermal vents in proximity to an underwater realm akin to hell.

Shrimp and crabs grazing bacterial mats on rocks near hydrothermal vents. Mariana Arc region, Western Pacific Ocean. Photo courtesy of NOAA.

Now new technology brings this world into focus like never before. In a session entitled "Doing Fieldwork on the Deep Seafloor," scientists at the 2011 American Geophysical Union (AGU) meeting in San Francisco described findings revealed by better access through torpedo-like autonomous underwater vehicles (AUVs), as well as improved cameras and multi-beam side-scan sonar, and in some cases, data processing that converts multiple 2-D images to 3-D renderings, which can be rotated and viewed at various angles. Together, these and other developments are contributing to intricate imaging and mapping accuracy never before achieved.

Minerals precipitated from hydrothermal vent fluids, photo courtesy of NOAA

For example, in summer of 2011, the Monterey Bay Aquarium Research Institute (MBARI) used the AUV D. Allan B to map fresh lava coverage of the seafloor. An area 10 million square meters large was mapped with astonishing horizontal resolution of one meter and vertical resolution of 20 centimeters, revealing the exact flow boundaries, lava pillars, and small flow features such as lava pillows. As presented by Bill Chadwick, et al., high-resolution bathymetry via the AUV also revealed further detail of earlier flows previously observed from visual features alone. According to their abstract, imaging of downslope ends of 1998 flows "show that large lobes of lava covered with pillows that are 200-500 meters in diameter, 10-20 meters thick" are arranged like shingles on a roof, and importantly, "show clear evidence of an inflation and drainout." Such observations imply surface hydraulic connectivity to an extent larger than that previously assumed for submarine lava flows.

Additionally, armed with high resolution, accurate maps and improved GPS for precise navigation, scientists can obtain samples of rocks, sediments, and biota from exact locations. As presented by Jennifer B. Paduan, targeted sampling by remotely operated vehicles (ROVs) permits scientists to age flows from rocks collected through coring and to follow changes in specific areas over time.