Learning to See

Willingness, mindfulness, focus, and detective work

the question is not what you look at–but how you look and whether you see. (Thoreau 1851)

In my weekly essays I commonly report small natural history observations noted during a walk in the forest or meadows. Readers of these essays sometimes ask me how I manage to notice the little things I frequently write about—a trail of a small beast in the mud, an odd excrescence on a twig, hairs caught on tree bark, a bee sleeping among goldenrod flowers. Well, that is easily answered: I am interested! And that is the starting point.

So if you think you might be interested in learning How to see, or How to see better, or How to see more, while taking a walk on or off trail, keep reading. And, although I am putting this in terms of seeing, the same principles apply to our other senses.

I think the process of really seeing things can be broken into four stages:

Stage 1. Being willing to become engaged in the process of observation of natural history. It is not necessary to be a naturalist at the beginning; as experience grows and observations accumulate, you have more background to build on, and a beginning naturalist is hatched. But it is entirely necessary to be willing.

Stage 2. This could be called mindfulness or ‘being there’. Although we often think about many things while taking a walk—maybe health problems, or what to make for dinner, or books you’ve been reading—take some time to be aware of where you are and what is around you. Even while talking with a friend, use your peripheral vision and let one part of your mind catch something that’s unusual or different. Maybe it is a change in pattern—an unexpected flower color, a dark spot in a field of yellow, a lump on a pine branch. Let it spark your curiosity.

Stage 3. Focus. Look more closely at what caught your peripheral vision and ask questions. Is it a flower that you don’t recognize? What are all those flies or bees doing? Why did those gulls suddenly fly up in a big swirl and move down the beach? What made those leaves roll up into cylinders? What could have made that narrow, wiggly trail in the mud?

Stage 4. Detective work. Try to answer at least some of your questions. This may involve more observations, or looking things up in a book or on-line, or consulting a local expert. Or you can be satisfied just by noticing things and looking more closely.

Photo by Bob Armstrong

Here is an example. You are walking on Perseverance Trail in summer. You are vaguely aware of a lot of white, flat-topped inflorescences on tall stems near the trail. You may or may not know the plant is called cow parsnip or Indian rhubarb. Most of the inflorescences might have a small fly or two crawling around—barely worth noticing, maybe—but one of them looks darker and has a dozen or so flies of various sizes, making it look different from the others. As you watch, you notice that the flies are probing into the tiny flowers that comprise the inflorescence, possibly eating nectar and pollinating the flowers as they move around. But one of the ‘flies’ looks a little different from the others; it has longer legs, a thinner abdomen. And as you watch, you see it probing flowers like the other insects but gradually sidling up to a feeding fly and pouncing on it! Wolf in sheep’s clothing! Not a real fly, but a predatory wasp.

That simple observation could lead on—to finding out the identification of the wasp and more of its life history, to reading about other sneaky predators, to figuring out the effect of the wasp on pollination, to looking for similar behavior on other types of flowers, and so on—depending on how much detective work you want to do. In short, you have discovered a STORY, one that could be expanded in several directions.

These activities are not the choice of everyone. But if you are willing, and have a little bump of curiosity, and take the time to pay attention, you will find many small stories—connections among things, contrasts or parallels among other things—and all of this enriches a walk.

It’s fun to do these story-searches by yourself. But it’s even more fun to do them with a friend. I have two dear friends that share this fun with me rather regularly (and whose thoughts contributed substantially to this essay).We complement each other, noticing different things, asking different questions, contemplating different answers. Try it!

The rare moment is not the moment when there is something worth looking at but the moment when we are capable of seeing. Joseph Wood Krutch 1951


Spring has sprung

excitement of the season grows with bird sightings, awakening bears, and skunk cabbage flowers

After a slow start, the season has sprung into full swing. The early avian harbingers have been joined by lots of other speciesin the first part of May. Out on the wetlands, flocks of small shorebirds and little brown songbirds swooped around and settled invisibly in distant sloughs or the brown grasses. Some of those little brown songbirds eventually turned into Lapland longspurs, savanna sparrows, and (near the forest edges) white-crowned sparrows.

On one lucky day, I saw four mountain bluebirds perched on the fence posts at the edge of the golf course; later I saw three of them perched on the tall, dried seed-heads of dock plants. That same day, three species of swallow (barn, tree, violet-green) coursed up and down one short section of a tidal slough. A big group of northern shovelers hung out on the river, more than I’ve seen together in one place previously. A few American pipits ran along the grassy edge of a slough.

Two days later, there were no bluebirds to be seen; maybe they took advantage of the good weather to make the trip over the mountains to the Interior. From the dike trail, I saw twenty-two white-fronted geese huddled on the river with a single snow goose. Out over the dry grasses, a northern harrier (in brown plumage, therefore female or juvenile) flew low, back and forth, and then dropped straight down to the ground and began pecking repeatedly at some invisible prey. Three ravens chased a hawk with agitated calls, disappearing into the distance. I had to wonder what that hawk had done—or was suspected of doing…

In other places: Kingfisher Pond hosted red-winged blackbirds, tree swallows, and a coot, with yellow-rumped warblers flitting in the shrubbery. Another observer there recorded Wilson’s warbler, green-winged and blue-winged teal. Hermit thrushes began to be heard in the forest. North Tee Harbor reported female bears with cubs, prowling about. A big bear wandered through my yard in the middle of the month. Little white butterflies flitted over the dandelions and emergent greenery. And fern-leaf goldthread flowers appeared along some wooded trails.

Rufous hummingbirds always appear at my feeder a couple of weeks or more after they are reported from Fritz Cove Road. But they finally showed up, perhaps a pair, but they visit the feederseparately, usually in the afternoon.

A male hairy woodpecker landed on my deck railing and was chased off by a squirrel. He came back a couple of times and visited the peanut butter offerings. I was reminded that in a previous year a fatherly hairy woodpecker brought his fledgling to the deck for daily lunches. Could that happen again? The local red-breasted nuthatches are making lots of trips to the seed feeder for sunflower seeds, quickly zipping back into the spruces, sometimes returning so soon that I begin to think they are just stashing the seeds somewhere, for later eating. I hope they will nest here again. A varied thrush comes to collect seeds from the deck railing, but it spends most of its effort on a suet feeder—lunging up to jab the suet with its bill while madly flapping its wings (not a graceful hoverer).

The big excitement on my home pond was the unexpected appearance of two pairs of wood ducks. I’ve never seen them here before, although they’ve been rumored to nest occasionally in the lower Valley. As of this writing, the wood ducks have been here for over a week, and I saw one pair copulating. They nest in boxes and tree cavities, but I have no idea if suitable cavities are available near here. They got along peaceably with the mallards that remained on the pond.

Wood duck male. Photo by Bob Armstrong

Sometime early in the month, all the females and most of the male mallards departed from my pond. A lone male floated on the pond for a few days and eventually was joined by a solo female who stayed for several days; they often rested side by side on the bank. I’m guessing that she had laid some eggs but lost them to a predator, and she was here to start another clutch. Mallards are ground nesters, relying on camouflage and concealment (and luck) to survive the long incubation process, but the eggs are vulnerable to wandering dogs, bears, ravens, and other predators.

One of my favorite things in spring is watching the skunk cabbage plants. First, the little green spears emerge from the shallow waters, but I impatiently await the cheery, brilliant yellow spathes that announce the flowers of ‘swamp lanterns’. The hood-like yellow spathe (if not nipped off by frost or deer) surrounds the spike (or spadix) of densely packed flowers. Each of those flowers is female first—with pointy little stigmas sticking out for potential pollen reception. But the earliest plants to bloom, being all female, have no source of pollen, unless they can somehow pollinate themselves, as the flowers mature into the male phase. Eventually, all the flowers become male, producing yellow pollen. Now we begin to see insects hiding down deep in the spathe, sometimes tiny flies and dozens of black beetles. The beetles are thought to be pollinators, crawling over the male flowers, eating pollen and getting it all over their bodies, then carrying the pollen to later-blooming individuals, still in female phase. We never see as many beetles hiding in spathes around female-phase flowers as in spathes with male-phase flowers. And female-phase individuals often have no beetles at all, so it seems that beetle visits to females are intermittent, and I suspect that females send out air-borne messages that attract the beetles just when the time is right for pollination.

Early male-phase skunk cabbage flower, with pollen just starting to appear. Most of the flowers are in female phase, with pointy stigmas. Photo by Mary Willson

The red alder trees along the highway are popping out little leaves, catching up with some of the shrubs that leafed out earlier. Now every day may bring some new development for the season—such fun!

Rough-skinned newts

an intriguing local amphibian

Juneau has four resident amphibians that breed in fresh water: wood frogs and western (boreal) toads, which have geographic ranges extending way up north, Columbia spotted frogs, which range to about the northern border of Southeast, and rough-skinned newts, which are at their northern limit in the Juneau area.

Adult rough-skinned newts are small, less than about eight inches long and have a pebbly texture on the back that gives them their name.
Photo by Bob Armstrong

These newts (Taricha granulosa) are a west-coast species, from California northward. As the glaciers of the great ice ages retreated, newts apparently expanded their range into coastal BC and then the island archipelago of southern Southeast; not too long ago, in geological time, they reached Admiralty and Shelter Islands. The move to Juneau, probably a few decades ago, is thought to have happened with human assistance.

How did they move north from one coastal island to another? There are several non-exclusive suggestions, but apparently nobody really knows. Perhaps not all of the present-day islands were separated by seawater when the big glaciers prevailed and more dry-land connections might have existed; then terrestrial dispersal may have been feasible in some areas, although land in front of the retreating glaciers would be perhaps too cold and barren. As the glaciers melted and sea levels rose, however, this potential pathway would disappear (unless the land, gradually released from the weight of ice, rose enough). But freshwater drainage from melting glacial ice would make a lens of fresh water on top of the sea water. Could that have helped dispersal? Or did they come down the big river drainages from the interior? But there is no known population source in British Columbia. Or did they get carried around by Native kids as pets, and eventually released on various islands? Or can adult newts tolerate seawater, at least for short periods? Exposure to salty water is known to have deleterious effects on newt embryos (and those of other amphibians), the degree of damage depending on the salt concentration and temperature, and very salty runoff from ice-melting roadway salts is bad for adults too. However,apparently the newts in some populations can tolerate brackish water. It might be surprising for an amphibian to tolerate salt water, although toads can, to some degree. But I have, so far, not found a study of salt tolerance in adult newts. The questions remain unanswered!

Rough-skinned newts (and a variety of other critters) are well-known for a powerful neurotoxin (TTX for short) in the skin, which causes paralysis and is usually lethal to a consumer. However, toxicity varies among populations; for example, newts that live above 500m elevation are much less toxic and can be eaten by mammals and other predators. Toxicity also varies among individuals within many populations. 

Various species of garter snakes are known to be resistant to this neurotoxin even in large doses (and egg-eating caddisflies areresistant to the toxin in newt eggs too). Most other predators are reported to be killed when the toxin is ingested (although they survive when eating newts from nontoxic populations). Garter snakes in areas with the most toxic newts tend to be the most resistant. The snakes are reported to be able to judge the toxicity of a newt by grabbing and partially swallowing it, rejecting the newt if it is too toxic. In turn, a newt can smell if a snake has recently eaten another newt and try to avoid it. 

The initial, and appealing, story was of a co-evolutionary arms race between predator and prey. The arms race means that the more toxic prey escape more often, so more resistant predators then become more successful; they eat more newts and there then is natural selection for more toxic prey, which in turn favorsmore resistant predators, and so on. But the initial story was tested by exceptions: populations with no correspondence between newt toxicity and snake resistance, and now researchers suggest that various other factors are probably involved too. (Note: specimens from a particular lake on Wrangell Island and from Juneau were very toxic…but there are no garter snakes there; garter snakes are extremely rare in Southeast). Research continues.

Adult newts have dark backs and orange ventral surfaces. Toxic and venomous organisms often advertise their dangerousness to would-be predators, commonly with bright color contrasts. The combination of blackish and orange or yellow is one of these warning colorations, as in bumblebees and wasps. When an adult newt is threatened, it typically adopts a distinctive posture: arching the back, bending the head back over the shoulders and arching the tail over the body, thus displaying the warning colors. This color display deters at least some predators (and the presentation of a peculiar posture might look difficult to grab). 

Newts are carnivores, eating a variety of worms, snails, crustacea, insects, spiders and such, as well as the eggs and tadpoles of other amphibians (and sometimes those of their own species), and occasionally small frogs. Adults are semi-terrestrial, often occurring under logs and other damp places on land.

They mate in fresh water in spring (at low elevations; later at high altitudes), sometimes migrating overland to suitable pools. A courting male becomes smoother-skinned and slimy. Heclimbs onto a female’s back, hugging her behind her forelimbsand wrapping his hind legs around her abdomen. He rubs his chin on her nose, releasing chemical signals from his chin gland. If she is receptive, she lifts her head, and the pair stays clasped together for an hour or more. They change their positions, and he releases a spermatophore, which she picks up with her cloacal vent. Then the male usually mounts the female again for a while (sometimes many hours), which prevents other males from interfering while the sperm are entering her reproductive tract. Competition among males is said to be intense, and the mate-guarding behavior protects a male’s investment.

A pair of rough-skinned newts beginning the process of mating in a local pond this spring. Photo by. Bob Armstrong

Two or three weeks after fertilization of the eggs, a female lays them, singly, attached to vegetation. The eggs are toxic, like their mothers, and hatch in three or four weeks. Tadpoles have frilly, external gills and forage on protozoans and other tiny organisms on the vegetation, sometimes eating smaller tadpoles. Tadpoles metamorphose into adult form the following summer or the next summer, depending on the weather. Newts don’t mature until they are four or five years old, and mature females do not mate every year.

Inheritance of genetic and acquired traits

the complex science of epigenetics

Some Juneau friends planted holly bushes in their front yard a few years ago. Those bushes grew well, producing dark green leaves with smooth edges. However, during a few winters of heavy snow, deer foraged on the smooth leaves, as far up the bushes as they could reach. Juneau folks often note deer (or porcupines) browsing on garden plants. A common response of gardeners is to build a fence.

But the holly bushes built their own ‘fence’. The leaves produced after the deer browsing have spines on their edges, which dissuades deer from further munching. Somehow, the deer foraging induced a change in the leaf morphology. How does that happen?

To approach an answer to that question, we have to provide some background (and that leads to a more general issue of inheritance).

The suite of features that comprise the structure and function of an organism is called the ‘phenotype’. An individual’s phenotype typically determines (along with sheer luck, too) if it can survive and reproduce successfully. Holly phenotype includes the flexibility to produce different types of leaves. In their native habitats, that flexibility probably enhances theability of holly plants to survive and reproduce successfully. Thus, some phenotypes do better than others: they have higher evolutionary fitness—that’s natural selection. Much of a phenotype is determined by genes, so differential survival and reproduction of phenotypes generally means that some genes become more frequent in a population, while others become less frequent—that’s evolution, which sometimes leads to new species.

The physical basis of inheritance lies in DNA, which occurs in cell nuclei and in mitochondria (which run metabolic machinery) in the cell cytoplasm. Genes typically are segments of a long DNA molecule; we identify them as units of inheritance by observing what they produce and then by detailed molecular analysis. The information contained in a gene is expressed in the building of proteins and other molecules essential for life. Some genes determine a structure or an enzyme or a process, while others modify expression of other genes or repair DNA damage (some do nothing we can detect).Genes can change, through a process called mutation. Although many mutations are repaired before they are expressed, some persist, altering the organism’s phenotype—so they are a basic source of variation among individuals. Some mutations are beneficial, favored by natural selection and that phenotype succeeds, while other mutations are detrimental and that phenotype does poorly.

In addition, for centuries, it has often been thought that some traits acquired during the lifetime of an individual can also be passed on to the next generations. Such phenotypic traits are not based on the genes of DNA. For example, it might be suggested that if a giraffe made her neck longer by continually stretching out for more leaves to eat, she could end up making offspring with longer necks. That particular example does not work. But the contrast between this idea and gene-based inheritance fueled arguments for many years. As we learn more about the intricacies of inheritance, it turns out that certain types of acquired characteristics actually can be transmitted from one generation to the next.

We are not talking here about direct external impacts—if the tails of mice are cut off (changing the apparent phenotype), the offspring of the artificially tail-less mice have normal tails. A body-builder who has spent a long time developing big muscles doesn’t pass on those big muscles to his kids.

Instead, some internal, intracellular change brings with it a change in the expressed phenotype. It happens without any change to the basic physical structure of DNA (and is reversible in some cases). It alters gene expression, generally by blocking access to a functional part of the DNA but not changing the genes themselves. For example, sometimes a chemical group called ‘methyl’ is stuck onto the DNA, usually turning off gene expression for that piece of DNA. Or the normal twist in a DNA molecule is changed, such that a functional part of DNA cannot access the material it normally works on. These changes of gene expression are called ‘epigenetic’, the prefix ‘epi’ meaning ‘on top of’ or ‘over’.

Many of these epigenetic effects are normal, controlling development and changing with age. And some environmentally-induced epigenetic effects may modify the expressed phenotype of individuals without changing the next generations. A study of European holly in Spain showed that leaf browsing by mammals induces an increase of prickliness of the leaves, and this was accompanied by methylation of the DNA, which is presumably what happened to the hollies in Juneau. But the possible heritability of the prickly phenotype itself is still unknown, apparently.

However, environmentally-induced phenotypic alterations can sometimes be passed on to the next generations and have been reported for many organisms, from worms and insects to plants and humans.  Marked temperature changes, air pollution, diet composition, exposure to heavy metals, viral infections, stress, various medicines, exercise….the list of agents that can lead to heritable epigenetic effects is very long.  There may be heritable environmentally induced epigenetic effects on flower shape, longevity, leaf hairiness, eye color, fur color, body size,susceptibility to disease, and many other phenotypic traits. To provide one example, in a much-cited case for humans, severe malnutrition during pregnancy, associated with methylation at various DNA sites, resulted in offspring that were smaller than usual, and that also had more disease, poorer cognitive function, and shorter lives. Some of those effects also appeared in the grandchildren of the starved mothers.

The bottom line is this: Inheritance of acquired characteristics is a real phenomenon, in certain cases of environmentally induced epigenetic changes of phenotype. There has been a lot of research on environmental epigenetics, primarily on the molecular mechanisms and the associated phenotypes. Although it is widely recognized that such phenotypic changes can increase or decrease survival and reproductive success, it seems that there is still much to be learned about precisely how and when such phenotypic changes are adaptive or detrimental and thus potentially have an effect on the course of evolution.

A frustrated avian predator

a tale of predators and scavengers

The second week of April began quietly, with a few snow flurries and early-morning new ice on my home pond. The ice was gone by midmorning and on the ninth, the first mallards arrived. Males and females, they swam in the narrow open channel between the ice and the bank or loafed on the ice platform in the center of the pond. And they came every day thereafter.

Seeds on the deck railing attracted the usual juncos, chickadees, and nuthatches. But one day a raven came. It marched the full length of the railing, snapping up seeds of all sizes, one at a time. Reaching the end of the line of seeds, it turned around and did the same in the other direction, until its crop began to bulge. Raven visitations have been extremely rare this winter, and I wonder what prompted this one to come.

One evening, I glanced out my front window and saw a hawk sitting on a dark lump on the pond ice. A juvenile northern goshawk had killed a male mallard, and a few fluffy feathers were strewn about. The hawk had one foot clamped on the duck’s bill, with the other one on the body. As the hawk pecked at the duck’s head, getting small tidbits (the mallard was past caring), it frequently looked all around, as if to check for possible thieves. Then the hawk tore off some body feathers and took a couple of bites, grabbed the duck’s head with one foot and flapped laboriously over to a nearby snowy bank, the prey dangling limply and precariously just above the water surface.The duck probably weighed about as much as the predator, so this was quite a load (although goshawks are known to take prey more than twice their own body mass).

A very damp juvenile goshawk tries to drip-dry on its perch. Photo by Mark Schwann

Once on the bank, the hawk changed its foothold from head to wing, but the prey slid down the steep little bank into the pond and floated immediately under a ledge of snow that stuck out from the bank. Now the hawk had a problem: from the bank above the duck, all it could grab was a wing, while the body was lodged under the ledge. The hawk tried several times to haul the body up over the ledge and onto the bank, taking intermittent rests in nearby trees. By now, it was starting to get dark, and the frustrated, slightly bedraggled hawk took off for a nighttime perch somewhere else. Apparently, the hawk never figured out that if it pulled the wing toward the ice, the body would come out from under the snow ledge and be available. Alas, no photo of all this action was possible without disturbing the process.

Meanwhile, although a squirrel scolded continuously, avian activity on the deck railing continued as usual, with the addition of a face-off between a nuthatch and a junco, which was won by the nuthatch. Ten minutes after the hawk left, other mallards came back to the pond where they’d spent most of the day.

By six-thirty the next morning, there was no sign of the dead mallard in the pond and no new scuffle marks in the snow on the bank. There were muddy footprints, probably of a dog, crossing the ice platform, but at some distance from the place where the duck was last seen. Hmmm, did the hawk come back and figure out what to do or did somebody else appropriate the prey? That all left a frustrated observer too!

Ah, but late that afternoon, I looked out my window again. And there was a river otter, munching away at the carcass on the ice platform, not far from where the hawk had struggled with it. The otter tore big gouts of muscle from the keeled sternum and stripped the long bones bare, mauling the carcass in all directions to expose more edible tissues. By the time the otter went for a cleansing swim, there was just a messy pile of feathers, guts, and bloody bones. None of that disturbed the mallards loafing at the other end of the ice platform!

After the otter swam around the pond (which did scare the loafing ducks) and departed, an eagle arrived. It found a few bitsleft by the otter, gobbled up the intestine, tore the tough gizzard into chunks, and flew off with the bones of the pectoral girdle and parts of two wings in its talons. A raven arrived in the evening, but too late! Only loose feathers and bloody ice were left. And so the duck’s death profited three other critters. A fitting end to the story!

This nesting female goshawk in juvenile plumage attacked the photographer, giving him a good clout on the head with her fists. Photo by Bob Armstrong

Note: The bird I watched was probably a year old (possibly two): its plumage was very dark brown with no sign of transition to adult plumage. Goshawks sometimes start breeding when they are only a year old and still in juvenile plumage, perhaps chiefly in low-density populations where competition for territories is not intense, but tend to have low reproductive success. Some reports indicate that individuals that don’t initiate breeding until age three or four tend to have better nesting success. Foraging experience probably contributes to success at nesting (and having an experienced mate to share chick-feeding duties might help compensate for inexperience in one member of a pair), but many factors, including prey density, prey species, and habitat quality, influence nesting success. Detailed studies are few.

Bits and pieces in early April

encounters and observations

The first week of April brought us a little snowfall on several days. My home pond is still ice-covered, firm enough to support several transits by a big, galloping dog. The new berms are shrinking at last, and the one under my deck shows the old tunnels made by a neighboring squirrel in search of spilled seeds. One of my (indoor) cats is a regular window-shopper for squirrels, but one day his ears were unusually perked and he was very intently focused on something not far away. So of course I looked out that window—and saw a shrew exploring the old squirrel tunnels. The cat may not have seen one of those before, so his curiosity was roused.

Out on my deck, I’ve spread some bird seed on the railing, a temporary offering until I can restore the feeder than hangs over the pond. The winter gang of juncos is reduced to just a few (mostly males) and flocks are still seen in some places, although some can be heard singing and getting ready to mate; it seems like the juncos collectively aren’t quite ready for spring. The chickadees are fewer too, presumably setting territories somewhere. A pair of nuthatches seems to be resident and I hope they will raise another brood this year. Sometime in March, I began to see a pine siskin—just one. (How often does one ever see just one of them??). For two or three weeks, there was just one, and then suddenly there were two; an occasional third one was quickly chased off. Could they be nesting nearby?

A walk on the dike trail at low tide revealed a sizable flock of juncos; these were not yet setting up territories and advertising for mates. A loose flock of robins moved about in the grass, not settling long in any spot. On the river, eight or ten buffleheads, both males and females, kept together, occasionally diving but never straying far from the others. Dozens of mallards loafed on a sandbar, a few swimming desultorily just offshore. Not far from them was a very different duck, diving regularly. The bright russet head and upper neck suggested perhaps a Redhead; I did not see a pale crown stripe that would name it a European widgeon. Several trail-walkers notice a large, white bird, floating all alone, in a lagoon way across the river. We couldn’t tell which species of swan it was. Although tundra swans go to the far north for nesting, trumpeters don’t go so far and sometimes nest near the north end of Lynn Canal.

Photo by Kerry Howard

Along the Outer Point/Rainforest trails, wrens and varied thrushes were singing. A red-breasted sapsucker energetically tapped on a dead tree, sending out notices of his presence and readiness for the season. Not far away, I noticed a fallen hemlock trunk with old sapsucker wells all in a tidy vertical row. I’ve previously seen arrays of sapsucker wells that occupied patches of ten or twenty square inches on some trees. But those trees were willows and alders, which have smoother bark than hemlocks. So maybe the vertical row of wells was opportunistically exploiting a channel between thick bark ridges where the bark was thinner.

Sapsucker wells. Photo by Mary Willson

On the way down to the beach, a loud rattle was soon accompanied by a second one, not far away. It soon became apparent that two kingfishers were having a serious discourse, just above the tree canopy. They did not visit the rocks at the waters’ edge but went somewhere else, out of sight. Out on the beach, no mermaid’s purses (embryo cases of skates) had yet appeared in the washed-up piles of seaweed, although in other years they sometimes have shown up about this time. Just off-shore, a seal floated by on its back, sculling slowly along with just its nose and chin above water. Oddly, that seal was the only visible vertebrate critter in the bay; usually that place is more active.

Mendenhall Lake is still frozen and a few risk-taking skiers have been seen out there. The gulls are already circling and calling above the lake, contemplating a return to their nesting places on the west-side rocks, and then flying back out to sea–for now.

On a rainy day, the Boy Scout trail was a very quiet place. In grassy meadows, red berries of an herb sometimes called (very inappropriately) false lily of the valley or mayflower lay on the ground, awaiting the arrival of migrant thrushes that would gobble them down and disperse the seeds. Beach rye showed greenish shoots a few inches tall. Geese arrived in pairs, but there was one loner; eventually they all grazed together peaceably. I suspect these geese are our resident ones, already paired up. Gulls loafed on sand bars or frolicked in the water nearby. A scattering of big, empty horse clam shells dotted the lower beach. A flock of fairly small, apparently black birds with white wing patches whizzed by and may have been pigeon guillemots, although this seems a bit early for them. Two immature eagles were wading in the shallows while adults perched high in the trees. Not a single raven invited itself to a picnic lunch on the beach.

To end the week on a cheering note: the temperatures at my house crept up over fifty degrees for the first time this year.

Roots, shoots, tumors and bone spurs

adventitious growth can help or hinder

We sometimes see plant roots growing from stems or branches (rather than from seeds), or small, leafy shoots appearing on tree trunks far from the leafy canopy. The term used for that in biology is “adventitious growth’. The word adventitious is used in many ways and has many proposed synonyms (reflecting the varied usage), but I’ve not found one that applies very well to the biological situation.  There it might be described as tissues or structures that emerge from (initially) unexpected parts of an organism—not in the main place for such tissues or structures to develop. Nevertheless, in some cases it is a regular occurrence.

Consider, first, what causes adventitious growth. Some kind of stimulus (often environmental) wakes up some cells, which start to divide, making new tissue. In some cases, undifferentiated cells (not committed to making a particular kind of tissue) are lying dormant and would remain so without that stimulus. In other cases, the stimulus causes already-differentiated cells to de-differentiate and then re-differentiate to make a new kind of tissue. Quite amazing! The nature of the stimulus is varied—maybe a stress, such as too much water or a wound or pressure, or an infection, or perhaps some unexpected input of resources.

Sometimes the extra growth can be useful to the organism, sometimes it has no evident significance (beyond the cost of making it), and sometimes it can be harmful.

Adventitious roots are common in many kinds of plants. Trunks and branches of fig trees and mangroves send down aerial roots that eventually reach the soil and serve the normal root functions of taking up water and nutrients. Corn plants commonly develop numerous adventitious roots in addition to the main root system (which comes from the seed); they grow from the lower stem and eventually provide the normal root functions and also brace the upright plant. Strawberry plants send out above-ground stems called stolons (runners), and roots can develop when nodes on the stolons contact the ground; a new plant may grow there—it’s a form of vegetative propagation and part of the way strawberry plants colonize new ground. In plants such as these, adventitious roots are common, regular features that contribute to the plant’s survival and reproduction.

So-called ‘sucker shoots’ often develop on trees that have been damaged in some way. They come from cells that were just lying dormant under the bark. But if lots of tree branches are torn or cut off, the dormant cells wake up and build new shoots that eventually produce leaves. Contrary to the name, these shoots don’t parasitically suck out nutrients; ultimately they help replace the lost photosynthetic capacity of the original branches.Kalanchoe plants, mostly native to Madagascar and tropical Africa but often cultivated, produce many tiny plantlets at the edges of the leaves; the tiny plantlets drop off and can establish themselves in the soil—a form of vegetative reproduction . Horticulturists can propagate begonias (and some other plants) from cuttings and leaf fragments, applying nutrients and certain chemicals that induce the cuttings and fragments to produce new little plantlets from previously dormant cells.

There are also cases in which adventitious growth is harmful to a plant. Crown galls are tumors or cancers (terminology depending on the researchers) that form in response to certain microorganisms or fungi. They disrupt the flow of water and nutrients, weakening and stunting growth of stems and roots. They are seldom lethal, however, because their growth circumscribed and limited.

However, in animals, it’s a different situation. Cancers are often damaging and sometimes lethal. Many kinds of factors contribute to cancer, damaging the genes that control cell division. So the cells with damaged DNA divide uncontrollably; in some cases they are impervious to the immune system that would normally eliminate them, they may attract blood vessels that supply nutrients and remove metabolic wastes, they may even make their own nutrients in a novel way. The uncontrolled growth creates problems with normal functioning; and the cancer spread to other parts of a body, creating more problems there.

Some other examples: Skin moles are little lumps that form on human skin (other animals too?); the causes are variable and little known. They come in various colors and shapes and can be unsightly, but they are not usually harmful (although some rarely turn cancerous). Bone spurs can develop in vertebrate joints when cushioning cartilage is worn down and adjacent bones put unusual pressure on each other, causing bone cells to grow into the joint. (It’s normal for bone cells to grow under pressures; that’s why staying active helps keep bones strong; so when spurs develop, the cells are doing the normal thing but in the wrong place). But the bone spurs can interfere with joint movements.

Spring comes slowly

Musings and sightings in a lean season

Winter came late this year—the good snows and cold temperatures didn’t arrive until after the new year began. One last observation from the winter: the creeks in the Dredge Lake area were frozen, and their icy surfaces held mini-forests of feathery ice crystals. A shrew had ventured out among those feathery tufts, mowing down a channel through them, leaving a trail rather like a big caterpillar. 

The vernal equinox has just passed and the now-dirty and rotten snow still lies over much of the ground. I looked out my front window at all that snow and my ice-covered pond a few days ago and was swept by a wave of nostalgia for the deciduous forests of the Midwest, with their wonderful array of flowering woodland ephemerals that bloom in early spring before the trees leaf out. When I was little, an elderly neighbor lady took me for walks, just to look at them. Years later, I learned to appreciate them in a different way, when my grad students and I studied the pollination biology of seven species of white-flowered ephemerals in Illinois woodlots. Other species soon flowered too, all taking advantage of the sunlight reaching the forest floor before the canopy closed. Never-mind that March is a tad early, even for those early-flowerers—I must be very ready for spring events here.

Trail-walkers comment on their impatience for the arrival of spring, and I’m just as eager as they are for the exuberant burst of spring that’s still in the offing. Meanwhile, signs of spring are appearing slowly, almost one by one. A couple of deer along the highway still had their thick, dark winter fur coats. But we hear juncos singing in many places, varied thrushes and wrens are tuning up, and robins forage in beach grasses. A dipper is singing at Steep Creek. The serious declines in bird populations here and elsewhere make each sighting or hearing more valuable than ever. Mountain goats are seen quite regularly near Nugget Falls, as they rest in the infrequent sunshine and look for edible lichens. Squirrels have done their mating chases. Elderberry buds are fat and almost ready to open; new shoots of devil’s club are becoming visible at the tips of the prickly stems.

As I await more and bigger signs of spring, there have been good things to see along the trails. One day at Fish Creek, a rotund otter rested at the edge of the ice that still covered most of the pond. After a few minutes, it dove and came back up in a crack a little farther offshore. There it dove repeatedly, but if it caught anything at all, the prey was very small.

Photo by Jos Bakker

Lots of elderberry bushes grow at the edge of the woods on the ‘island’ at the end of the berm. A friend and I were curious about bud development, so we inspected the branches. Yes, the buds were growing but, more interestingly, almost all the twigs at the branch ends were missing, chewed or torn off, although a few of the tallest branches had escaped mutilation. I have seen porcupines demolishing elderberry twigs and deer are known to browse woody vegetation in winter, especially when snow is deep, so there are two likely perpetrators—if they ever wander out to that ‘island’.

Out on the wetlands, an anomalous spindle-shaped form caught my eye, and binoculars revealed it to be the back view of a heron, standing sleek and still. It turned a little bit, and I had a beautiful view of its light-colored chest feathers, all fluffed out and fluttering in the breeze. I’d never seen such a huge ‘chest beard’ on a heron. No other herons were visible; maybe it was merely drying out its plumage (?).

Near Shaman Island, a harbor seal floated placidly, sometimes making short dives but mostly just looking round. A flotilla of red-breasted mergansers cruised by, two males and four females. The males had their long, green crests erected and occasionally thrashed the water with their wings; there may have been tension between them, but most of their cruise looked peaceable. One of the females drifted away and went foraging, but the others kept on sailing. Red-breasted mergansers often over-winter in salt water bays and estuaries and move inland to nest near big lakes and rivers. This merganser regularly nests on the ground, unlike our two other species of merganser. Their name derives from Latin words meaning ‘diving goose’, but they bear almost noresemblance to geese. The diet is mainly small fish, with some additions from invertebrates, snapped up by that narrow bill. 

My eagerness for full-blown spring will not hurry it along, so I’d best settle down and patiently(?) enjoy whatever I can observe as the days go by.

Social bees

and social learning

Honeybees are very social insects, often living in large colonies under the aegis of a queen, who lays eggs that are tended by theworker-bees (all female). The workers forage for nectar and pollen in the area around the hive, bringing back food for the larvae. A successful forager often signals to her less-experienced nest-mates the location of a good food source (although other successful foragers may choose to continue with their own discoveries). The floral scent she carries stimulates her nest-mates to pay attention to the signals. Workers begin to forage soon after becoming adults, and then may start to follow a signaler as it signals; followers become better foragers than mere observers, but they don’t become signalers themselves until they have more experience.

Honeybee. Photo by Bob Armstrong

If the food resource is close to the hive (tens of meters), the signals are presented as a circular route performed on the surface of the comb by the excited forager. But if the discovered food resource is farther away, the signals take the form of a ‘waggle dance’. The waggle dance conveys information about direction, distance, and quality of the resource. The dancer circles first one way and then the other, making a figure eight, doing the waggle of its abdomen while moving its feet (‘running’ but not going far) on the short straightaway between the adjacent circles. This pattern is repeated a number of times. The orientation of the dance on the comb (or ‘dance floor’) tells other bees the direction to go, the duration of the abdomen-wagging ‘run’ on the straightaway tells distance, and the number of waggle runs tells about the quality of the resource. That basic story has been known for decades, but it turns out that there are also acoustic and air-flow signals from the dancer’s wing vibrations, about which much less seems to be known, and the dancers emit pheromones (perhaps stimulating recruits?). There may be tactile cues as well, occurring when a recruit follows a signaler closely enough to touch it with antennae. Some researchers call this a symbolic language.

That seems pretty straight-forward, and for species of honeybee that make their nests in the open, orientation by the sun is relatively simple—the dance is vertical if the direction is towards the sun, or it is oriented by the angle by which the resource deviates from the sun’s apparent location. But for honeybee species (such as the familiar western or domestic one) that nest in cavities, signaling orientation is a bit more complex. In these hives, the honeycomb is a vertical surface, and it’s dark in those cavities, no sun in sight. Somehow, these species have substituted gravity for sun-sights, but the angle of deviation from vertical still indicates the angle of deviation from the apparent direction of the sun. And furthermore, the bees are able to time-compensate for the lag between the dancing and the time of the next foraging expeditions, sometimes a matter of hours.

Experiments have shown that inexperienced bees that have teachers make fewer errors in their own dances than equally inexperienced bees not exposed to dancers. In short, not only do these bees learn from others about food resources, they also learn about how to communicate with each other—they are capable of what is called social learning, which means learning from teachers that actively pass on information.

The teacher-less bees learned to correct some of their own dance errors but never did learn to correct errors about distance, consistently over-estimated how far away the resource is. Some researchers suggest that such built-in error might actually be useful when the colony swarm to a new location and starts to explore the floral resources there.

Recognizing and integrating all that signaling information is a lot for a tiny brain (about one cubic millimeter in volume) to accomplish. But there’s more: the duration of the waggle run, the distance indicator, differs among types of honeybees, including different populations of the western/domestic species—there are ‘dialects’ in the coding of the distance-indicator. When a population in general has short foraging range(resources are distributed close to the nests), the duration of the waggle run is shorter than when their foraging distances are longer, and different populations misinterpret each other’s signals if they are experimentally mixed. That is to say that these bees have culture—socially learned behaviors that are transmitted between generations across whole populations.

Bumblebees are social too, although they live in smaller colonies, usually a few hundred bees. The worker-bees forage for nectar and pollen to feed the larvae that the mother-queen produces. Foraging bumbles learn, by trial and error, how to exploit flowers of different shapes and arrangements of nectar glands and pollen-bearing stamens; they also learn how to open flowers that conceal their food rewards (such as snapdragons and monkshood). They tend to avoid previously visited flowers where other bees have left their scented footprints.

Bumblebee. Photo by Kerry Howard

When a bumblebee worker has become proficient at exploiting certain flowers, she commonly tends to specialize on those flowers, seldom visiting those at which she is less efficient. These bees are capable of learning from each other by observation, as shown by laboratory experiments, but how often this occurs in wild bees has apparently not been recorded. They do use pheromones (airborne scent signals) to recruit their nest-mates to go foraging, and the recruits often start by sampling flowers with the aroma of the flowers visited by the successful forager. However, it seems that bumblebees do not actively teach each other about the location of floral resources, unlike honeybees. So, although bumblebees are very social, social learning may not occur in those species.  

But why not? What is the critical difference between bumblebees and honeybees that led to the difference in teaching and social learning? Perhaps active teaching helps recruit the greater numbers of workers needed to feed a large colony? OR….?


vampires of the natural world

Eating liquid blood (formally known as hematophagy) is a moderately popular way of life in the animal kingdom. Red blood cells are good sources of protein and iron. But they’re low in vitamins and they are not easy to digest. Critters with a bloody diet often share some particular features: they have sensory systems keenly attuned to locating their food source, a way to anesthetize the point of entry, and use anticoagulants to keep the blood flowing. Once they have ingested the blood, they digest the red blood cells with the help of special enzymes or gut microorganisms (which can provide vitamins) and excrete the excess fluid. 

The habit has evolved independently several times in different branches of the evolutionary tree; it’s wide-spread among the invertebrates but also occurs in some vertebrates.

Let’s start with some familiar ones (sometimes all too familiar).Although we can’t compete with the Interior in terms of summertime mosquito populations, we have enough of them here, at least in some places, to elicit bad words, bug dope, and head nets. Mosquitoes are basically nectar- and fruit juice-feeders, except when it’s time for females to gear up for producing eggs—that requires a more nutritious diet, and the females go for blood.

A mosquito’s food-getting apparatus is an ingenious thing. The slender proboscis consists of a sheath containing several specialized mouthparts. When a female has located a host, chosen a site, lands there, and is ready to feed, the sheath rolls back, exposing two narrow, toothed maxillae that saw a hole in the host’s skin, two narrow mandibles that hold tissue apart while the hole is sawed open, one skinny tube for sucking up blood, and another skinny tube that drips saliva into the wound. That saliva bears an anti-coagulant, dilates the blood vessel, blocks an immune response, and lubricates the whole works.

Photo by Bob Armstrong

This clever and complex arrangement is derived evolutionarily from the appendages of the four segments that form the head—quite a change from the earliest insects, which were chewers. However, similar systems for piercing and sucking have originated many times during the evolution of insects, e.g., bedbugs, kissing bugs, some lice, fleas, and a variety of plant-suckers too, such as aphids.

Lots of other invertebrates share the appetite for blood. For instance: An array of flies (blackflies, horseflies, deerflies, no-see-ums, etc.) as well as ticks have a slightly less elaborate anatomical approach. They slice or rasp a hole in the host’s skin, shove in the mouthparts, and slurp up the fluid. Other invertebrates of sanguinary habits include leeches, many of which take blood from vertebrates; you may acquire your own sample by wading or swimming in some of the Dredge Lakes.There are nematodes such as hookworms that live for part of the life cycle as intestinal parasites, feeding on blood.

No-see-um. Photo by Bob Armstrong

Among other invertebrates, there’s a so-called vampire moth of Eurasia that pierces the skin of vertebrates. There is a large marine snail (Cooper’s nutmeg) that parasitizes electric rays in the eastern Pacific, cutting a hole and inserting the proboscis;the tongue-like toothy radula may rasp away the flesh; other nutmeg snails might also have this habit. The vampire snail and some of its relatives have tiny radulas and apparently just suck blood from sleeping fish in a similar way. A certain spider is reported to get blood from a secondary source—by eating blood-filled female mosquitoes.

Among vertebrates, I found no reports of blood-eating amphibians or reptiles, but some fishes do so. The Neotropical candiru is a tiny freshwater catfish that swims up the outflow from the gill chamber of other fishes and latches onto the gills, which have a plentiful blood supply. Lampreys are jawless fishes of both marine and freshwaters; over a dozen species of them can attach their round, tooth-laden mouth to another fish and use a toothy tongue to scour a wound on the side, thenslurping up the blood and bits of other tissue.

A few birds are known to become blood-thirsty, at least at times. Oxpeckers of Africa graze on ectoparasites infesting large mammals and also eat the blood from the wound made by the parasite. Hood mockingbirds live on an island in the Galapagos Islands and sometimes feed on blood of wounded seabirds. The vampire finch, also found in the Galapagos, pecks wounds in seabirds and drinks the blood, particularly when other foods are scarce. The Tristan thrush lives on the islands of Tristan da Cunha in the south Atlantic; it supplements its diet of seeds and leaves, a variety of invertebrates, bird eggs, nestlings (and even adults) by taking blood from penguins.

I was interested to learn that the word ‘vampire’ probably originated as a term for human ‘witches’ and was only later applied to other animals, such as moths and finches. Surely, the best known vampires are bats, native to the Americas. . Vampire bats belong to the taxonomic family of leaf-nosed bats (although they have lost the nose-leaf), a group with varied feeding habits. The vampires may have originated from some fruit-eaters, or perhaps they came from ancestors that picked parasites off of host animals and acquired the habit of taking blood from the wound as well. Three species of bat are known as vampires, two feeding mostly on birds (and sometimes mammals) and one on mammals and large birds. 

The one specializing mostly on mammals is known as Desmodus rotundus, and that one is has been studied much more than the other species. A hungry Desmodus bat crawls up to a mammal on foot and clambers on. Its sensitive temperature receptors allow it to locate a blood vessel close to the skin surface. Then the very sharp upper incisors shave off the fur if necessary and slice a hole in the skin, the saliva keeps the blood flowing and provides some pain-killer, and the bat can use its grooved tongue to lap up its dinner. Specialized gut microorganisms are essential to digesting the blood meal. The meal is processed rapidly, to eliminate the extra fluid, so the bat can take off for its roost without carrying a load of fluid; once in the roost, the solid part of the meal is processed.

Young Desmodus bats feed on their mother’s milk, of course, but they soon start getting regurgitated blood from the mother.These bats roost colonially in caves, hollow trees, and other sheltered places; the groups are composed of females, their offspring, and a few males (the rest of the males roost separately). Roost-mates sometimes engage in mutual grooming. During that process, females sometimes share blood meals other females, not only their relatives but unrelated females also.That’s a form of reciprocal altruism, which can help maintain social relationships.

Weather and wildlife in March

wild and windy walks in a season of transitions

On a sunny day in early March, a friend and I went to Eagle Beach, despite windy conditions and a forecast of thirty-to-forty mph gusts. The weathermen had it right. The north wind was roiling up sizable whitecaps on Lynn Canal. The beach was covered with snow, untouched by the recent low tides, and obscured by billows of drifting snow. Instead of heading north on the beach, as I usually do, we cleverly decided to turn our backs to the wind and, hoods up, we walked down the beach and tide flats toward Eagle River.

Across the canal, the snowy Chilkats gleamed in the bright sun. A gang of gulls and crows concentrated at the distant edge of the tideflats, near the water’s edge. Perhaps surprisingly, given the stiff gusts of wind, a couple of groups of gulls were swooping over certain places in the estuary, as if there might be some prey stirred up by the churning waters.

But that was all the wildlife sign we saw, until we’d post-holed over the big meadow to the forest edge. My companion heard pine siskins and we then saw them, working over the cone crops in some tall spruces. There were squirrel tracks and a chattering squirrel. A vole had traipsed across a small open area, leaving footprints and tail-drag.

Best of all: lying on the snow near a big spruce, we found dozens of clipped spruce branches, mostly branch-ends with two or three twigs, all the needle tips neatly nipped off. That porcupine had spent a long time in this spot, clipping all those branches and needles, leaving greenish urine stains here and there, and packing down a well-used trail back and forth across our path. It left some fresh porcupine tooth-work on the base of a nearby hemlock, too.

A bit farther on, we noticed several trees patched with old scars of sapsucker foraging. Material had oozed around the edges of each bird-pecked opening and congealed there, making a rough surface over every opening. The scars on each tree were conspicuously concentrated in dense patches, just above our eye-level, not lower, not higher. Perhaps once a feeding site was started, the flow of sap was greater or at least more accessible there, rather than in a new place. But why did the birds choose those particular trees and those specific parts of the trunks to start feeding?

Returning to the car, it was more post-holing through snow drifts, almost knee-deep. Well-buffeted by those gusty winds, I staggered along, ready for the hot tea that was awaiting us in a handy thermos. Not a long walk today, but a productive one.

The next day was bright and clear again, and very windy, at least in open areas. Four friends met near the visitor center and looked for a packed-down trail along the east edge of the lake. No luck; blowing snow had drifted well over that. So we opted to go toward Nugget Falls on a narrow, packed trail over the flats where the terns usually nest. But that, too, meant post-holing through knee-deep drifts. So we cut over to the usual beach trail and then to the main trail, where we noticed wind-blown alder seeds all over the snow.

Arriving at the base of the falls, sharp-eyed observers spotted two mountain goats on the far side of the creek. One perched on a little rock outcrop and one stood at the edge of a brush thicket. Neither one was moving much, so I had a hard time picking them out. Those two were the first of the year, for me.

Photo by Kerry Howard

As we approach the vernal equinox, day-length is rapidly increasing; the daily rate of change is greatest near the equinoxes (and slowest near the solstices). Humans and otherorganisms notice the lengthening days—eagle start tending their nests, magpies start leaving for the Interior, buffleheads begin to be seen in pairs, and there’s an occasional song of wren or song sparrow. Red squirrels in my neighborhood have been doing a lot of vigorous chasing lately, and food is not the principal focus. Although these squirrels are strongly territorial for much of the year, when females start coming into oestrus, territory borders are commonly crossed in the search for mates. Both sexes often mate with several other individuals, and so litters may have several fathers. Roughly five or six weeks after mating, litters of up to seven young ones appear in the females’ nests.

Although some of the felt-leaf willows have fat buds, other plants lag behind. You can be sure that they have noticed the longer days, but other factors, such as soil temperature, are not yet right for gearing up in ways visible to us. As the longer days gradually warm the soil, more and more plants will show signs of activity, some of them waiting to flower until well after the summer solstice when days are shortening again.

Felt-leaf willow buds. Photo by Kerry Howard

Seasonal transitions are always fun, as we notice each new sign of activity. After a slow start in late winter, the signs speed up through the spring and into the summer. Although skiers may revel in the persistent snow and longer days, others eagerly await the beginnings of green-up and the first flowers.