A Wintery Walk

a wonderful weasel encounter

Days are rapidly getting shorter, and the peanut butter junkies at my feeders are voracious. The familiar Oregon juncos that thronged the feeders all summer are now scarce. But I’ve begun to see slate-colored juncos, here from the Interior for the winter. Closely related to the Oregon types (both are usually classed as subspecies of dark-eyed junco), but the new arrivals took at least a week to figure out how to exploit the peanut butter feeder. Maybe they watched the chickadees and got the idea.

On a lovely, sunny but cool and windy, day in mid-October, a little group of friends strolled up the road at Eaglecrest to go off onto the upper ski loop. Darting in and out of the angular rocks that line the road toward the Black Bear lift was a small white critter that disappeared almost as soon as it showed its head. So it took us a little time to ascertain who it was: of course, a short-tailed weasel or ermine (called a stoat in Europe). It then gave us many chances to see it as it explored both sides of the road, around the turn and past the Kimball memorial bench, popping up its head every so often to look around (and perhaps to check on us). The weasel was presumably hunting for something edible, such as a vole or shrew, but we saw no evidence of success.

Photo by David Bergeson

The white winter fur was certainly conspicuous against a background of gray rocks and brown fern fronds. When there’s snow on the ground, of course it’s a different matter—the white fur is great camouflage then, only the black tail tip and a beady black eye marking the beast on a white background. “Our’ weasel apparently had turned its coat from summer brown to winter white well before snow would cover the ground (although a little dusting fell a few days later). Molt is said to be initiated by changes in photoperiod (day length), and modified by temperature, but southern ermine don’t change to white at all. In northern populations, the physiology of molting to winter color is not closely timed to reliable seasonal snow cover; in fact, on snow-free Haida Gwai’i, ermine still acquire a white winter coat. This leaves open a question about why molt is not better synchronized with background color everywhere.

Weasels are built long and slender, which enables them to slip into narrow tunnels, even into vole hideouts in pursuit of prey. However, that elongated body has a lot of surface area (where heat is lost) relative to body volume (where heat is generated), so weasels have a high metabolic rate that generates heat– but necessitates lots of food. An active hunting style presumably provides more encounters with prey (than a sit-and-wait style, for instance), but has its own energetic costs. They need to eat several times a day (taking in about thirty percent of their body weight!) and have a well-insulated nest (often stolen from a victim) in which to rest between hunts. If the usual prey of small rodents is scarce, weasels may hunt hares, squirrels, birds, and even eat worms and bugs and carrion if necessary. They cache dead prey for future meals.

Mating season is in spring, but fertilized eggs are not implanted in a female’s uterus until nine or ten months later. Then the embryos develop into babies in about a month, the newborns staying in the nest for a couple of months or so. Litter size is variable, usually four to eight kits, but well-fed females can produce much larger litters (up to eighteen kits!). Juvenile females become sexually mature while still in the natal nest and may (if a mature male was nearby) already carry fertilized eggs when they disperse to establish their own home ranges. Males can’t inseminate their female litter-mates because they don’t mature until about a year old.

Here are a few more interesting tidbits about weasels: They have excellent color vision, unlike most mammals. They climb well, with reversible ankle joints (like squirrels) so they can descend a tree head-first. If threatened by a superior predator, such as a cat, they may pretend to be dead; if not eaten, they quickly revive and run away.

At this time in October, there was a thin sheet of ice on my home pond in the morning and the ponds at Eaglecrest were ice-covered. Nevertheless, we saw caddisfly larvae in their cases, hanging out on the bottom of a few ponds or moving extremely slowly. They probably spend the winter as larvae, feeding on detritus when possible, but otherwise quiescent; pupation and metamorphosis into flying adults would occur the following year.

A few blueberries clung on their bushes, and I was informed that they were exceptionally tasty. The bright green fronds of deer fern and fern-leaf goldthread stood out on a background of brown, dead and dying vegetation. On the surface of some old skunk cabbage leaves, tiny pools of water had coalesced and frozen solid, forming jewel-like, nearly spherical beads that gleamed in the sunlight.

We ate our lunches in warm sunshine, all spread out in the lee of a grassy bank. The first wintery walk of the year turned out to be a good one.

Three fungal curiosities

a tree-swallower, a “bleeder,” and a “nest”

This essay is about an eclectic assortment of fungi, my choices being based entirely on happenstance and whim.

One September day on the Outer Point trail, we spotted a very large, yellowish patch on a tall alder snag. That patch covered most of one side of the snag; at a guess, it may have exceeded ten square feet. At first glance I thought it was a huge crustose lichen, but no, it was a fungus. On certain places on this expansive crust, there were small ridges like miniature conks, and on their undersides were numerous pores where spores would be produced. The crust has covered mosses and engulfed the stems of licorice ferns.

Photo by Jennifer Shapland

I went back to look at it about ten days later, and now the surface featured many shallow furrows that had turned brown. The furrows were four or five millimeters wide and several inches long, crisscrossing the flat surface of the big fungus. Were they the work of slugs or land snails, grazing their way along? No, there were no marks of the scraping radula or tongue. A few days later, another observer suggested that wind-bent branches hit the fungus. No, when I tried it, small branches striking the surface didn’t leave furrows like that. A few more days later, we finally noticed that all the furrows occurred between human knee height and head height. Then I found that I could mimic the furrows very well with the flat of a fingernail. So we—finally!– concluded that these furrows are just graffiti. Much less interesting than slug trails, but perhaps closer to truth. ‘Twas a shame to deface such a beautiful organism.

What is this magnificent, hall-of-fame specimen? It seems that nobody really knows! It might be X or maybe Y, or something else altogether. Several mycologists have been consulted, with no concrete results. A sample sent to a lab for DNA analysis might yield a solid answer.

A strange fungus sometimes seen near the visitor center, among other places, is called the bleeding tooth fungus (Hydnellum peckii). Its name is not about bleeding teeth; it’s a tooth-fungus (with spore-bearing ‘teeth’ instead of gills or pores) that seems to ‘bleed’. The immature cap is white, but sometimes there are little pools of red fluid on the surface. Another name, perhaps for the more squeamish observers, for this critter is strawberries and cream. As far as I can tell, nobody really knows why those pools form on the cap. The present idea is that it’s a way to get rid of excess moisture, as some other fungi and some plants do by exuding droplets of water. But why are the pools red? Is the color just an incidental by-product of some metabolic process?

Photo by Jos Bakker

This fungus is mycorrhizal, forming connections with the roots of conifers and exchanging nutrients. The cap turns dark as it matures and produces spores. The stalk is thick and short, so short that the cap is often semi-buried in moss and debris. That raises the question of how the spores get dispersed from under the cap.

Yet another curiosity is a bird’s nest fungus (Nidula candida), a decomposer living on dead wood and rotting vegetation that is quite common around here. It earned its name from its appearance: the mature, reproductive form features a small (roughly one cm) cup containing several little round (somewhat flattened) objects. So it resembles a miniature bird’s nest with eggs. The ‘eggs’ contain spores. The cap is ingeniously built so that a raindrop can splash the ‘eggs’ out of the cup to a distance of a meter or more. The ‘eggs’ of some bird’s nest fungi (but not ours) are ejected with long, sticky threads, which catch on vegetation as they fly off. Eventually the ‘eggs’ deteriorate, releasing the spores. The spores germinate, producing stands called hyphae; two hyphae of the right mating type can merge to develop a nest-like fruiting body. Splash-cup dispersal mechanisms are uncommon means of spreading offspring around, but they are known also from some plants.

Photo by David Bergeson

Bright spots

after a soggy summer

The autumn equinox is past, and the days are rapidly getting shorter. It was an exceptionally rainy summer and we can’t expect fall to be much different. Sigh. But there have been some bright spots along the trails in forest and meadow.

One happy sighting in a meadow on the Peterson Lake trail was a bird busily foraging in the mosses, but it was partly obscured by clumps of taller vegetation. All I could see was a brown back and bits of moss flying every which way. I watched for a few minutes, but the flurry of flying moss continued without revealing the forager. So I slowly crept in a circular path to get a different perspective and eventually won a quick side view of the bird’s head. Ah…a red mark on the face and maybe a dark spot on the chest. Then the bird took off, exposing a big white rump patch (but not the colored underwings). OK, of course! A northern flicker, a woodpecker known to forage often on the ground. They nest here occasionally, but I’ve only seen them in Southeast once before this.

A female flicker peers from her nest cavity on Douglas. Photo by Bob Armstrong
This male flicker has the red face mark of the western form and the red nape mark of the eastern form, so it may be an intergrade. Photo by Bob Armstrong

Another enjoyable sighting occurred near the Spaulding Meadows trailhead. A brown creeper zipped across the trail, landed on a tree trunk, and hopped its way up, using its tail as a brace in proper creeper fashion. It was soon followed by another one, which also landed on a tree trunk. But this one quickly moved onto the underside of a branch and hitched its way along, upside down, using just its sharp little claws. It seemed to be quite comfortable in that position and put on a nice little show of its expertise.

We don’t have to go to Vermont or Wisconsin to see good fall colors, even though we don’t have the great stands of oaks and maples. Our colors tend to come in smaller patches, but they offer their own visual treats. A band of cottonwoods on the far shore of Herbert River somehow managed to glow in yellow and gold above a swirl of river mist, despite a steady rain. Willows often turn yellow, but some bear vivid displays of orange and red (why??). The multi-colored leaves of highbush cranberry can be yellow, pink, bright red, crimson, or combinations of those. On the forest floor, bunchberry leaves make carpets in shades of yellow, orange, and red. I also enjoy the pale yellow tapestries of enchanter’s nightshade leaves that call attention to this tiny plant. Still smaller but eye-pleasing are the several kinds of red berries—devil’s club, bunchberry, red huckleberry, bog cranberry, and best of all, the translucent, almost-glowing highbush cranberry. These ‘little points of bright’ matter!

Not to be ignored are the woolly-bear caterpillars, the larvae of the spotted tussock moth. As they grew, they passed through several molts and changes of appearance, and the last instar has the familiar black bands on front and rear with a yellow or orange band in the middle, with some long white tufts. They eat leaves of deciduous trees, but in fall we see them crawling around, looking for a place to build a cocoon and spend the winter.

Fall rains also liven up the lichens and mosses, which are looking quite happy. Fall-fruiting fungi appear—including some showy white ones with a vase-like cap (since I’m a ‘fungignoramus’, I won’t attempt to provide a name).  

The Herbert River trail has always seemed rather dull (until you get close to the glacier area)—lots of the same thing for a long way. But that is unfair! There are actually zones of changing vegetation as one goes up the trail, quite noticeable when I pay attention.  And recently I found several colonies of what turns out to be a common species called the stiff clubmoss, bearing its cones on the tips of the twigs—and thus easily distinguishable from the running clubmoss, with cones on long stalks. How I managed miss the stiff clubmoss all these years, I don’t know, but now that I’ve learned it, I have discovered it in other places too.

For a curious naturalist, sometimes a bright spot (of a sort) comes in the form of a mystery. Along the lower part of Eagle River, a little above its junction with the Herbert, I noticed an odd collection of animal scat. There were maybe fifteen deposits, all within about two meters of each other. They had a variety of sizes and shapes, from cylindrical to lumpy, and all were black. Bears would seem to be the most likely perpetrators. But why so many scats in one place? Bears just defecate where they happen to be and don’t—as far as is known to several wildlife biologists—make communal latrines. One suggestion is that a family of bears had a secure resting place somewhere nearby and used that place for an extended time. But does that account for the very localized deposits? The mystery remains.

Bristletails

often-overlooked insects from evolution’s earliest days

Arctic bristletail. Photo by Aaron Baldwin

Bristletail is a name applied to several different kinds of small, wingless insects, all of which have three long, thin appendages at their rear ends; these ‘tails’ often bear lots of little bristles, hence the name. Official taxonomy, however, now divides them into separate categories. Here I am focused on one group, called the jumping bristletails—because they can jump several inches up and away from a perceived threat. The jump is accomplished by using some of their six legs and body flexure.

Jumping bristletails are one of several groups that arose very early in the course of insect evolution. They’ve been around for about 400 million years or so, ever since most of the land plants were mosses and lichens. A modern representative known as the Arctic bristletail (Petridiobius arcticus) lives on our rocky shores. A careful look at certain parts of the shoreline in daytime might reveal them as they forage and sun themselves and occasionally jump around or at least their molted exoskeletons stuck on a rock; however, they are reputed to be more active at dusk and night. They share their shoreline habitat with harvestmen, millipedes, slugs, spiders, and who knows what else.

This species eats mostly lichens. Young ones hatch from overwintered eggs in early spring. Growing and molting through the summer, they are near mature by autumn.  They overwinter again, in rocky crevices or under moss, and continue to grow through a second summer, reaching maturity at the end of that summer. That’s when mating occurs (the process in this species is so far undocumented by scientists), and eggs are laid in moss and debris among the rocks.

In general, the various species of jumping bristletails occupy a variety of habitats, including leaf litter and under stones, in bark crevices, in places ranging from high in a tree canopy to deserts and the arctic. They feed on algae and organic debris, as well as lichens and mosses. Their exoskeleton is very thin, so they are often at risk of desiccation. The small body, less than an inch long, is covered with small detachable scales that might make them difficult for a predator to grab.

They are unusual insects in several ways. In their lifetime of up to about four years, they molt many times, three to five times a year or even more, depending on how fast they are growing. When ready to molt, they glue themselves to a hard substrate and crawl out the old exoskeleton. Young and old ones look alike except for size; there is no metamorphosis. They may take two years to mature. After some courtship dancing, most reports say that males typically accomplish mating indirectly: they spin a silk thread and attach packets of sperm there for a female to pick up. It is not clear just when the eggs get fertilized…perhaps when the eggs are laid. Females scatter their eggs in crevices and other protected places, where they may remain dormant for several months.

Bristletail exoskeletons. Photo by Bob Armstrong

One arboreal species can steer its descent from the tree canopy with a long filament extending from its rear end. The filament has been shown to be necessary for a successful glide and for landing. Who knows what other amazing things may emerge as we learn more about these unusual insects!

Little invertebrates like these must have many predators. Spiders are reported to eat them. Foraging birds are likely to pick them up. Who else?

Thanks to Aaron Baldwin, ADFG, and Matt Bowser, USFWS Kenai, for helpful information, and to Bob Armstrong for spotting the array of exoskeletons that led to this essay. See Bob’s videos at his website www.naturebob.com.

Club Mosses

and the evolution of land plants

Common club moss. Photo by Bob Armstrong

On a recent walk near Echo Cove, I noticed a lovely patch of a club moss sporting dozens of erect spore-bearing ‘cones’. We have several types of club moss here, but the only one I recognize (so far) is Lycopodium clavatum or running club moss. It often has long stems that are covered with short leaves, and they ‘run’ over the ground before making erect branches that bear cones on stalks. Despite their common name, club mosses are not mosses at all; they are on a different branch of the evolutionary tree.

I knew that they originated a long time ago, although they were not the first plants to live on land. But seeing this modern specimen made me think about the evolution of early land plants and the problems that attend a change from an aquatic to a terrestrial environment.

The first land plants belonged to a group of green algae (called Charophyta), some of which became terrestrial perhaps 500 million years ago. It is not clear why they did so, although some researchers suggest that land-living allowed escape from various alga-eaters in the water. But land-living meant that these early colonists risked desiccation: both the plant and its spores had to be protected from drying. This could be done in two basic ways: avoid the problem by growing and producing spores only in wet conditions, or develop water-impervious layers around the plant and its spores. Furthermore, although they were already able to photosynthesize carbohydrates (from carbon dioxide and water), now they had to get the necessary carbon dioxide in a gaseous form, from air. Most of the early land plants were very thin, often only one cell thick, so gases could readily diffuse in and out.

The first non-algal land plants were liverworts and mosses, appearing roughly 450 million years ago. These plants grow close to the ground or other surface, seldom extending upward more than a few centimeters. Although they live on land, they need at least a film of water for reproduction: sperm have to swim to reach eggs to fertilize. They occupy two branches of the evolutionary tree that are adjacent to each other but totally separate from the branch that leads to all other living land plants.

Around 430 million years ago, there was a new development that changed everything. It is not well understood how it happened, but some presumably moss-like land plants developed vascular tissues that conducted fluids from one part of the plant to another, so they were no longer dependent on diffusion. That made a big difference! Thus were born xylem, for conducting water mainly upward, and phloem, for conducting carbohydrates from the green leaves to the rest of the plant. This made possible the development of root systems that both anchored the plants in the ground and allowed the uptake of water from the soil. It also made possible the vertical development of woody stems that raised the leaves well above the ground surface, reaching more light and air, and eventually developing large trees.

One of the first offshoots of the major lineage called vascular plants–which now could exploit both the soil and the aerial space above ground–was a cluster of minor lineages that included the club mosses and quillworts.  Among the fossils of the early forms of club moss was a tree that sometimes grew to be 100 feet tall. Unlike the trees we are familiar with, the trunk of these tall club mosses was not stiffened mainly by wood but mostly by its bark. Some researchers suggest that these trees grew for a number of years but died after reproducing once. They were once widespread on different continents but faded away by about 300 million years ago. That left the un-treelike forms to continue and they are with us yet.

Still to come were the ferns (there were now-extinct types that made seeds) and other familiar modern plants. These invented seeds by covering embryos with maternal tissue. The added tissue provided more protection from drying and often developed structures adapted for dispersal on land. In most cases, the enclosed embryo was also endowed with a packet of nutrition for seedling growth. They developed pollen grains to carry sperm cells through the air so they were not dependent on water for reproduction. Eventually the developmental pattern of some leaves changed, producing flowers for attracting pollinators.

The world changed entirely with the arrival of an array of vascular plants with seeds and pollen. Now there were grasslands and forests providing habitat as well as more food and more ways to get it for more kinds of animals, which embarked on their own various evolutionary trajectories.