Of Love and Dancing

The albatrosses began to return in late October.  One day I looked out from our cook tent and there were perhaps a half-dozen of the huge white birds standing serenely on the sand, looking both grave and comical with the stark, sharp beauty of sea-gray wings folded crisply across their backs.  They waddled uncertainly over the dunes to just the right spot, there, that's the nest, right there.  A few days later, there were hundreds, and a week later, thousands.  Their season on the tiny speck of sand in the middle of the Pacific had begun.

 Laysan albatrosse pair on Laysan Island.  Photo: J. A. Gervais, 1992

You can find Laysan Island on most world maps, although it is only about a mile and a half long, a mile wide, and cradles a large super salty lagoon.  Essentially it is nothing more than a large sand dune perched on a remnant volcano.  There isn't much else out in this part of the world, a thousand miles northwest of Honolulu, and Laysan is the second largest of the Northwestern Hawaiian Islands.  For a few years over a century ago, it was inhabited, briefly, by humans, who mined the guano, harvested the albatrosses' eggs, and killed the birds for their feathers.  It has belonged to the birds for many thousands of years.

Land is a rare commodity in the middle of the ocean, and all seabirds are tied to it for breeding.  The birds of Laysan do a time-share, where different species come in from the far reaches of their wanderings and breed at different seasons.  Winter belongs to the bonin petrels, the black-footed albatrosses, and Laysan albatrosses.

Blackfooted albatrosses dancing, Laysan Island.  Photo: J. A. Gervais, 1992.

The albatrosses were mostly quiet at first.  It must be very strange, to land on unyielding ground for the first time in nine months, and the newest arrivals seemed to suffer from the same "sea leg" syndrome that people do.  They wobbled around and studied the clumps of bunchgrass and their neighbors in silence.  But as the few birds swelled to thousands, the singing and dancing began in earnest.

Albatrosses dance.  These are spectacular dances, involving wild bows and snapping beaks, with some individuals becoming so excited they gape and scream, whipping their heads back and forth.  They whinny and moo and clap that huge beak.  Sometimes they throw themselves up on tiptoe and point skyward, with a soulful moan at the apex.  The black-footed albatrosses have a different dance than the Laysan albatrosses, but both dances are exotic, energetic, and incredibly noisy.  Living on a colony numbering tens of thousands of pairs is like being in the middle of a demented barnyard.

Laysan albatross skypointing.  Photo: J. A. Gervais, 1992.

We quickly learned that young albatrosses were so anxious to get going with their adult lives that they would throw themselves into a frenzied performance if we just waved two fingers back and forth in front of them, mimicking the first moves of the dance.  When we failed to deliver the correct response partway into the performance, they would retreat hastily, looking flustered.

I tried coaxing a few of the pairs who settled into spots right around my tent into a cross-species tango.  These birds' mates had already arrived, and after a few passionate rounds of dancing it seemed that old ties were renewed well enough to get down to the business of breeding.  Waving fingers in front of these birds elicited a sidelong look.  The albatross would draw in its chin, that huge, hooked beak held down along its neck, and waddle emphatically away.  Sometimes interspecies communication is shatteringly clear.

Every now and then, a Laysan albatross and a black-footed albatross mate, and raise a chick.  The chick, however, is doomed to be completely unlucky in love, because its dance is stuck halfway between the species.  Nobody seems to want a partner who can't do all the right moves.  The vast majority of birds belong to one species or the other, however.  Nearly all find a partner and stay together for many years, renewing the relationship each autumn with the ritual of the dance.

Blackfooted albatross dance on Laysan Island.  Photo: J. A. Gervais, 1992.

I worked on Laysan for a magical four months, picking away at invasive grass that provided shelter for none of the birds, but crowded out the native bunchgrass that nearly all of them need.  Although the work was far from special, sneaking by sea turtles and monk seals, admiring the antics of boobies and albatrosses, and watching tropicbirds and frigatebirds engage in aerial warfare made even plodding over sand dunes carrying backpack sprayers full of herbicide the best job I ever had.

I left Laysan Island on a November morning nearly twenty years ago, and I still dream sometimes of the intense color of the sea, the enormity of the sky, and the noise of all those birds.  It was an early love, one you don't forget, even if you go on to fall in love with many other places.

Do we need the wild?

A friend threw out a question she was pondering, which in turn had been posed to her by another friend.  "Do we need the wild?" 

At first pass, I thought the real question is why we ask this question, because my immediate answer was absolutely yes.  We can only ask this question if we see ourselves as somehow separate from "wild", however we define it.  At its worst, the question betrays the extraordinary level of artificial separation a small percentage of humanity has been able to create, on borrowed time and stolen resources, from the natural systems that sustain us.  We can maintain it only briefly and at increasing environmental, social, and economic cost.  When viewed from this angle, the real question is how long can we keep up the charade.

Petroglyph, Olympic National Park, WA.  Photo: J.A. Gervais



However, the question becomes far more interesting and far more complex on further reflection.  The Wild is the world beyond the comfortable circle of light thrown around the campfire ring, the impenetrable and sometimes terrifying world that harbors gods, demons, and other spirits that are beyond our control and often deaf to our supplication.  We are a part of this Wild, certainly, but more as stepchildren watching deep rituals beyond our capacity to master or to understand.  This Wild is one we fear and venerate, the one we approach with intermediaries and sacrifices held out as flimsy shields to protect ourselves even as we seek it.

This Wild has largely been forgotten in a human world whose cultures are increasingly dominated by materialism and gratifying any immediate whims, where the idea of something larger, something out beyond our self-imposed fence of goods and gratification, has been exiled like some sort of childhood legend for which we have no further need.  Most of the time, until some catastrophe slips out of the darkness and across the circle of self-imposed limit, laying bare the belief that we are all we need.  War, natural disasters, sickness, and loss of those we love to things that have no purpose are windows back into the dark and dangerous world we cannot control.

Stone circle, Island of Arran, Scotland.  Photo: J.A. Gervais

What draws us outside of ourselves, calls us to any higher purpose or holds us to any greater standards that might require us to act directly against our own immediate interests?  What guides us to see ourselves as taking our place within the larger mystery, which holds both the inanimate earth and all of the life forces within it?

This is the realm of the spiritual.  Arguably, we need to acknowledge our ties to this dimension of our world just as much as we need to acknowledge our dependence on fertile soil, fresh air, clean water, and the other inhabitants of land and ocean.  We may find echos of the spiritual Wild in a church, or a temple, or out in the woods; what resonates within each of us is a function of our culture, our upbringing, our experiences, and is deeply personal.

Do we need the wild?  Do we need souls and the spiritual, the belief in something greater and more durable than ourselves?  The two questions are really one and the same.

Olympic mountains, WA.  Photo: J.A. Gervais

Road Kill

There are two more dead deer lying along the road that ends just a few miles from town.  One is a doe, probably pregnant, the other a young buck just out of rut.  Someone has stopped and sawn off the antlers of the buck but both carcasses remain in the ditch, apparently inaccessible to scavengers.  They are hardly visible from a car, and possible to overlook even from a bicycle, as the cold weather has prevented the usual tell-tale smell.

We think of roads as opportunities for our own rapid movement and convenience, if we think about them at all, not the ribbons of death that wind through the home ranges or migration routes of many animals.  Stand at a rest stop along a busy interstate and see how many seconds pass in which there are breaks in traffic from one side of the highway across all lanes to the other side.  Not surprisingly, research has shown that roads can be major obstacles to animal movement.

How much roads cut off movement depends on not only the traffic load but the animals themselves.  Some animals such as urban gray squirrels seem almost oblivious to the traffic despite the risk and frequent near-misses.  There are video clips of urban wildlife using crossroads and even apparently waiting for lights to change before they cross.  They include deer, gray squirrels, coyotes, and Japanese crows.  The crows, of course, can easily fly over the traffic, but it seems that some of them have figured out that if they drop nuts into the crosswalks, cars will run over them, and the cracked nuts can be retrieved when the light changes.  These animals have adapted to live in the new world we've created for them.

But the vast majority haven't adapted.  Desert bighorn sheep populations are already showing reduced genetic diversity in just four decades after interstate highways threaded among them, raising the risks of extinction for the now-isolated populations.  Cougars avoided two-lane paved roads although dirt roads did not deter them.  Both wolves and elk in the Canadian Rockies avoided roads and trails in national parks as their traffic increased, but elk were less repelled and actually used the areas near moderately busy trails as predator-free zones because the wolves appeared more sensitive to the disturbance.  There are gradients in responses, and consequences.

At the other end of the spectrum, freshwater turtles don't seem to recognize the danger.  Turtles moving between two wetlands in Florida were willing to attempt to clamber over a barrier made of plastic netting to cross the busy highway separating the wetlands; nearly all those that succeeded were killed.  Populations of turtles near roads have a sex ratio skewed towards males relative to populations away from roads. More dead  female turtles are found on roads than males because the females are driven to leave the safety of water to find nesting sites.

The biggest issue may not be just the body counts, as staggering as they may be (upwards of 350 million wildlife deaths per year in the United States).  The worst thing about road kill may be what it reveals about our own fundamental thoughtlessness.  We are the one species that seems able to contemplate killing in an abstract way, evaluating the moral and ethical consequences of taking another's life.  The vast majority of us would not describe ourselves as careless killers, and would claim to avoid causing senseless death when possible.  Then we get into our cars.

The speed limit on the road with the dead deer is fifty miles an hour.  Every branch of this winding road ends a few miles farther into the hills, serving an exurban bedroom-community development.  People claim to like living in the country because they enjoy nature, but nature had better not get in the way of easy access to town.  Of course, very few wildlife-vehicle collisions occur on purpose; after all, people are often also victims of severe injuries or death when large animals like moose are involved.  But nearly all animals that are hit die.

When animals die of natural causes besides predation, they tend to die in places where scavengers can get to them, so that the occasion of death is also an occasion for the continuation of other life.  One of the elements of roadkill is its wastefulness, because the traffic may prevent scavengers from at least cleaning up after our carelessness.  Worse, other animals may be attracted to the bounty then also die in traffic.  This is only one aspect of the particularly repugnant facets of road kill.  Another facet is its anonymity, with neither killer or victim aware of the other.  It is the ultimate in thoughtless take.

The vast majority of victims are not ever seen before being hit, especially if they are low to the ground and cryptic, like snakes, lizards, or salamanders.  It is easy to ignore the carnage if you never see it, easy to believe that you don't contribute to it, easy not to think about it at all.  What if we did think about it?  What if seeing a dead animal, even a snake or a slug, required a moment of reflection and grief?  We would have to slow down enough to see the corpses.  If we slowed down, there would be far fewer of them.  That would be one benefit.  The process of acknowledging the losses might have a far greater benefit, that of helping us recognize our own place in the scheme of life, the first critical step to salvaging our planetary home.

Tale of Two Skinks

There are two edges to the sword of change that is slicing through so much of the biological skin of our planet.  The first is the staggering loss of biological diversity, adding up one of the great waves of extinction in Earth's history.  Along the trailing edge, ecosystems and the species that evolved in them are under increasing pressure from species new to the system.  We pay a lot of attention to the problem of extinction, but much less to invasion, even though it can and does contribute to the former.  It is perhaps a bit easier to rally to save a charismatic species such as a panda rather than organize to fight the diffuse threat posed by signal crayfish or purple loosestrife or kudzu.  However, scientists have started asking why some species become so destructively overabundant even though close relatives may be on an endangered list. 

Behavior alone won't dictate success.  Species that establish in new places also tend to be introduced over and over,  increasing the odds that eventually, a few individuals will survive the initial colonization event.  This in turn may be dictated by who lives where the most common transport routes start.  However, individual behavior seems to play a larger role than we expected.

Kudzu consuming a barn in North Carolina. Photo: NASA

If you want to successfully colonize a distant planet, you might consider taking a close look at how this works right here at home.  First, you've got to get yourself on some kind of transport vehicle, whether in the gut of another animal or the hold of a trading vessel or cargo plane headed elsewhere.  Realize you're probably not a welcome passenger, so you've got to be discreet.  You have to survive the journey, which means somehow finding or maintaining conditions in which you can live, with enough water, warmth and energy to avoid death.  Once you arrive, you need to sneak out of the way lest you be caught in the act and exterminated.  Very few stowaways make it this far, but the journey isn't over yet.  You need to find appropriate food, water, and shelter in these new, unknown surroundings.  Eventually, you need to reproduce successfully, which means you need to find, recognize, and successfully interact with a mate.  Next, your children must also raise children.  The resulting little community must avoid being found and eradicated, and finally, new colonists must leave and establish more communities before the invasion can be considered a success.

The odds, in short, are heavily stacked against you.  However, even if animals don't get help (in the form of deliberate introductions by people, such as starlings in North America, cane toads in Hawaii and Australia, or possums in New Zealand), some species still manage to pull it off.  We've just started to think about how animal behavior influences the risk of successful invasion.

Delicate skink. Photo: Peter Robinson, Museum Victoria, Australia

The delicate skink, Lampropholis delicata, and its cousin the garden skink (Lampropholis guichenoti), illustrate the point.  The delicate skink is native to eastern Australia, but has managed to colonize New Zealand, Hawaii, and Lord Howe Island.  The closely related garden skink, however, has stayed home even though it is quite similiar to its more adventurous cousin in many ways.  The two skinks are similar in size, have similar diets, and similar life histories.  Both species live together in urban areas in Australia, close to transport hubs such as major shipping ports and airports.  Both are common, and occur at high densities, suggesting no lack of individuals available for export.  What, then, is different?

Although both skinks like to explore new environments, the delicate skink was far more willing to move through a tube when it couldn't see the exit, enter a small black box in the test cage, and walk up a graveled ramp to reach a heat lamp suspended above the cage floor.  A greater willingness to explore, then hide, may explain a good part of why delicate skinks are called plague skinks while garden skinks have been at worst temporary tourists who never established outside their native range.  The opportunity to become a problem appears to be the same, but the behavior of the animals influences who takes advantage of that opportunity.

Garden skink.  Photo: Peter Robinson, Museum Victoria, Australia.

Not all delicate skinks successfully found the elevated basking site; animals, after all, are individuals.  Other research found that individual mosquitofish vary in their tendency to strike out for new horizons.  Interestingly, fish that chose to disperse also seemed less tolerant of other mosquito fish, and these personality traits were consistent in individuals over the study.  There may need to be a range of personalities and behavioral tendencies to support a successful invasion from start to establishment. 

We don't often think of the individuality of wild animals, or how much that might matter to the survival of a species.  If we were better at recognizing the individuality of non-domesticated animals, how might that change our view of them?



Sources
Chapple, D.G., S. M Simmonds, and B.B.M. Wong. 2012. Can behavioral and personality traits influence the success of unintentional species introductions? Trends in Ecology and Evolution 27:57-64.


Chapple, D.G., S. M. Simmonds, and B.B.M. Wong. 2011. Know when to run, know when to hide: can behavioral differences explain the divergent invasion success of two sympatric lizards? Ecology and Evolution 1:278-289.


Colautti, R.I., I.A. Grigorovich, and H.J. MacIsaac. 2006. Propagule pressure: a null model for biological invasions. Biological Invasions 8:1023-1037.


Cote, J., S. Fogarty, K. Weinersmith, T. Brodin, and A. Sih. 2010. Personality traits and dispersal tendency in the invasive mosquitofish (Gambusia affinis). Proceedings of the Royal Society B 277: 1571-1579.

Driloleirus macelfreshi lives!

This week marked the third anniversary of a significant scientific discovery made by my dogs.  We were out on a walk on a messy afternoon marked by mud, driving rain, and wind, courtesy of a Pacific winter storm.  Young dogs still need their walks, and so do their owners.  I can't really say quite how it happened, other than as I bent down to discharge my responsibility as a dog walker after my old dog had finished her business, I glanced back and saw the young one standing with a long pinkish stringy thing hanging from his jaws.  He looked quite pleased with himself, and was an instant away from flinging up his head and consuming his prize.  I witnessed this in the split second between discovery and annihilation. And somehow I knew that he absolutely must not be allowed to eat this thing, not for any risk to himself, but because of what it was. 

I leaped at him, howling at him to drop it, which is absolutely not how you are supposed to train a six-month old pup to surrender highly desired objects.  Fortunately for science, he was so shocked at my behavior he did drop it, and in his moment of indecision I swooped on his find and scooped it into a spare plastic bag.  The dog was utterly unimpressed at my inexusable theft of what he regarded as rightfully his.  There are times when I wonder whether he still remembers this.

At that time, however, we went home, and I laid the dog's find out on the counter.  It was an earthworm, and it measured four feet four inches long.  It was flabby, pale pinkish-gray, impossibly thin, and quite dead.  It was also the first specimen of the Oregon giant earthworm, Driloleirus macelfreshi, to be documented in twenty-seven years.  We know very little about this species, other than it seems to be endemic to the wooded bottomlands of the Willamette Valley.  It had been pretty much assumed to be extinct.

There are many little pieces to this discovery, each of which made that sudden, instinctive recognition on my part possible.  Over a decade ago, I had the great fortune to meet two of the last earthworm taxonomists in the world, Dorothy McKey-Fender and her son, Bill Fender.  This in itself was a culmination of improbable circumstances, but the crux was a workshop, conducted by Dorothy who was then in her eighties, on how to identify native earthworms.  The workshop was followed by a search for native worms in 2000.

Bill Fender and Dorothy McKey-Fender with a specimen of Driloeirus macelfreshi in their laboratory in 2000.  Photo: D. K. Rosenberg

I know a little about earthworms, as much probably as any average gardener or curious naturalist knows.  Native worms have been largely replaced by exotic species, and most of the worms we see as we go about our daily lives are descendants of recent immigrants to this continent as most of us are.  Ecologically speaking, we do not even know what we've lost, because the native worm fauna has been very poorly studied and described.  We do know that different families of worms behave differently, and affect nutrient turnover and soil humus in different ways.  We do not understand all the implications, although they include reducing the humus layer, which is itself a vital habitat for many organisms, and allowing exotic weeds to establish on the surface of soil no longer protected by that deep blanket.  For the most part, though, we just don't know what we've broken or what pieces remain somewhat intact.

There are earthworms out there, native worms, very different from the nightcrawlers we all immediately identify as the ultimate worm.  Even more amazing, there happens to be a gigantic native worm called the Oregon giant earthworm, Driloleirus macelfreshi.  Dorothy McKey-Fender herself had studied most of the specimens that have ever been collected- a scant few dozen in all.  They were far too rare to allow the workshop participants to examine, but Dorothy moved around the lab room set up with dissecting scopes and trays filled with other worms pinned to the black wax, delighted to share some of the knowledge accumulated over a lifetime.  Her love and respect for these animals was palpable, and her excitement contagious.  I've been more aware of worms since then, for their own sake, not just for what they do.

So there we were, in a wet riparian forest at the tail end of a storm dumping heavy rains, swelling the Willamette River until it licked and curled at the bases of the cottonwood trees along its banks.  A party of several people and several dogs ahead of us had walked right by the corpse of the giant worm lying on a bed of fallen leaves, not far from the floodwater's edge.  I would not have noticed it either, if my young dog hadn't loved to eat dead things.  But at least in that instant of seeing it, I was open to the existence of giant native worms.  Without that, the discovery would not have been possible, even if I had still looked straight at my dog in that instant before he snatched and swallowed.

Looking for another giant worm- the last one was right around here somewhere...

The worm is now among those in the McKey-Fender collection, although a small segment of the tail sits in a vial on my desk for possible genetic analysis.  More importantly, we know we can still look along the rivers and woods and hope for more than we recently dared hope for, that one of the unique forms of life on this planet may still be with us.  If we can be open to those possibilities, I hope we can also be open to more creative visions of how to live more gently and equitably among all of our fellow species.

Leaves in Grass

Our neighbors have gone south for the winter, seeking climates where it does not rain six days out of seven.  They leave by Halloween each year, before the rains have really set in, and return when spring is still early enough that wet cold days are the norm even as the Indian plum sends out graceful arcs of cream-colored flowers.

I've been thinking about communities lately, both ecological and human.  We take it as a given that the natural world is made up of many interconnected pieces, so that no single organism stands by itself.  For some reason, we have a much harder time accepting this view of our own communities, even though it is every bit as true.  This matters, as how we manage the coming enormous upheaval on a planet in rapid climatic transition will depend on how we see each other, and our relationship to both the rest of humanity and to the larger biological community of which we are an indivisible part.

The leaves have fallen in the neighbors' garden, thick enough to smother the grass if they remain there until spring.  I took the dogs and a rake and wheelbarrow and went to work, sweeping up the remnants of last summer's photosynthesis and depositing them in the garden plot.  Leaves are extraordinary.  They do all the work of taking sunlight, which in itself is simply energy, and transforming that energy into actual food- both for the plants, and for nearly all the rest of the non-plant life forms on the planet.  It is a very cool trick.  An even more amazing part of the trick is to shed the biomass when it becomes more of a liability than an asset, first salvaging the good stuff before letting the depleted leaf fall free.  The rest of us get a blaze of colorful glory before the curtain falls and winter takes the stage.

We have an understanding with these neighbors.  In the summer, they allow us to pasture our ewes and lambs on their five-acre pasture, and keep an eye on the water trough.  They've helped us build fences, taught us how to deliver lambs that are too tangled to come out on their own, and loaned us innumerable tools.  They've shared vegetables, gardening knowledge, tips on livestock care, small gifts, and great stories.  They are the sort of neighbors most people only know of through a culture of yesterday. 

In return, we help as we can, share lamb and blueberries and fresh bread, and keep an eye on their place when they go away for the winter.  I rake leaves and I can never quite believe that the summer is really gone, our neighbors are gone, and now there is the winter to be gotten through before we look down the hill and see their lights shining, breaking the darkness with a friendly light that says the neighborhood is as it should be.  The leaves have got to be gathered up first, and given a chance to move through the next stage of the cycle.

Shed leaves are a major component of soil humus, providing food and shelter for all manner of soil organisms.  I leave a fair number of scattered leaves as I rake, so they will provide fodder for the earthworms and enrich the soil that in turn supports the tree.  They'll be long gone by spring, and they are scattered enough so they will not impact the grass.  I use a bamboo rake and a wheelbarrow, because they get the job done while leaving me with the peaceful late fall afternoon, broken by the happy huffing of my dog in hot pursuit of his tennis ball, which I throw between sweeps of the rake, the calls of small flocks of juncos and chickadees, and once the sound of a tree falling in the woods by the creek.  It was wet and windy the day before, and the cycle of renewal incorporates more than just leaves.

I finish before dark, but not before the cold of evening flows in along the creekbed next to the garden, and the sheep start looking expectantly for some alfalfa pellets in their feeder.  Properly done, the afternoon's work will nourish both the human community and the wild one, with no loss to either.  Surely we can find a way forward that truly honors that which we value most.

Newts

One of the reasons I love living in western Oregon is that winter brings another season of life rather than a frozen dead spell, when most organisms either flee or hibernate until spring.  A few mammals and birds tough it out where winter brings snow and ice, but the woods are pretty quiet besides the sound of bare branches scraping in the wind.

Here, the tree branches are free of leaves now thanks to some Pacific storms ranting across the coastal mountains.  The branches aren't bare, however.  The forest is turning a new shade of green, one with delicate pale-gray hues, as the lichens unfurl on every small branch and twig of the oaks and maples.  Thick rugs of newly revived liverworts and mosses embrace the trunks and larger branches.  The snakes and lizards have disappeared, but the rough-skinned newts are out, marching along on their rubbery legs as they begin to move toward their breeding pools.

Photo by Miguel Viera, Flickr Creative Commons

The rough-skinned newts, Taricha granulosa, appear when late fall finally eases the harsh seasonal drought with the misty rain.  The newts are both numerous and active during daylight, unlike any of their kin.  They are encountered more often than they are noticed, judging by the number of flattened corpses on the road leading to the forest gate, and sadly, even in the woods where vehicular traffic is replaced by bicycles and walkers.  It isn't always adaptive to look like a somewhat rotten stick when viewed from above.

Rough-skinned newts tend to freeze in place if startled, although they can move along at a good clip if they decide they need to.  They are patient, and will stand motionless in mid-stride for many minutes if disturbed.  Their second line of defense is to curl in a distinctive ring, head thrown back, tail arched toward their throats, exposing their undersides in bright warning.  This dance to avoid being eaten is called the unken reflex, and it is shared among salamanders, toads, and frogs who defend themselves using chemical warfare as a last resort.

Unken reflex.  Photo by Ap2il, Flickr Creative Commons.

In the case of the newt, the bright orange color is backed up by tetrodotoxin, a potent neurotoxin, one shared with the blue-ringed octopus, a few toads, and some fish, most famously the puffer fish.  The Japanese serve a dish called fugu, which ideally offers the adventurous diner tingling lips but if not expertly prepared, leaves the victim paralyzed then dead through respiratory failure.  The Seattle Audubon Society's book Amphibians of the Pacific Northwest(1) reports that people have died from eating newts in the genus Taricha, although they do not reveal the circumstances.

How exactly such a diverse group of organisms have hit upon the same defense strategy is still unclear, although some researchers have suggested that symbiotic relationships with bacteria who synthesize the tetrodotoxin may explain the pattern(2).  Not everyone agrees, however, that this is how the newts acquire their chemical weaponry(3).  All stages of the newt are toxic, and mothers seem to pass on the poison to their eggs.(4)  Individual newts have variable levels of the toxin(5); presumably it is biochemically expensive to manufacture, and you might get by with a less stringent defense if your enemies expect all members of your species are equally bad for the digestion.  The predators, however, are on to the game.  Common garter snakes (Thamnophis sirtalis) have immunity to the poison(6), although they may become toxic themselves from the tetrodotoxin that builds up in their livers after eating several newts(7).  Larval dragonflies will snack on larval newts, and seem able to discriminate the palatable individuals from those best left alone(8).  Ultimately, any strategy is a gamble, and staying alive means playing the odds.

The chemical-defense strategy may not be the best option in this new world dominated by humans.  Cars do not notice unken reflexes, nor do fast-moving bicycles respond to poison.  Newts can live a long time if they avoid tetrodotoxin-resistant snakes and savvy dragonflies.  Like many long-lived species, they reproduce slowly, with few offspring reaching adulthood.  Their populations are poorly equipped to lose many members to novel death traps.  When I find a newt on a road or a popular path, I promptly give it a lift to the other side, hoping it will keep moving away from the ribbon of danger it cannot hope to comprehend. 

In December, we'll begin looking in the drainage ditches and small ponds in our area, hoping to see the graceful, slow dance of the swimming newts as they gather to mate, then lay eggs long before the first buds appear on the trees.

References (for the terminally curious)
(1).Jones, L.L.C., W.P. Leonard, and D.H. Olson, editors.  2005.  Amphibians of the Pacific Northwest.  Seattle Audubon Society, Seattle, WA.
(2). Chau, R., J.A. Kalaitzis, and B.A. Neilan. 2011. On the origins and biosynthesis of tetrodotoxin. Aquatic Toxicology 21(3):131-141.
(3). Lehman, E.M., E.D. Brodie, and E.D. Brodie. 2004. No evidence for an endosymbiotic bacterial origin of the tetrodotoxin in the newt Taricha granulosa. Toxicon 44(3):243-249.
(4). Lehman, E.M. 2005. Tetrodotoxin as a maternally-endowed defense against egg predation in the rough-skinned newt, Taricha granulosa.  Integrative and Comparative Biology 45(6):1032.
(5). Hanifin, C.T., M. Yotsu-Yamashita, T. Yasumoto, E.D. Brodie, and E.D. Brodie.  1999. Toxicity of dangerous prey: variation of tetrodotoxin levels witin and among populations of the newt Taricha granulosa. Journal of Chemical Ecology 25(9):2161-2175.
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