Winter walks

think, consider and imagine

In late January, the Parks and Rec hikers visited Sheep Creek Valley, a place we seldom visit at that time of year. The ground was frozen sufficiently that the mudholes on the uphill trail were no bother, and all that earlier warm weather had cleared the usual iceflow that commonly covers a side-hilling trail segment in winter; no problem there either.

Aside from a few fresh squirrel tracks, wildlife was not in evidence. In the uppermost part of the valley, below Hawthorne Peak, we could see snow squalls, which eventually came down to the main valley. The light dusting of fresh snow, and the seasonal absence of leaves, brought into clear and delightful relief many features of micro-topography that are normally obscured: drainage channels large and small, ridges and hummocks, rock outcrops. As I looked up the big ridge on the north side of the valley, I noticed a series of smaller, parallel ridges that ran up the side of the main ridge. Each of the smaller ridges had a rounded side, facing up-valley, covered with green moss and a few shrubs. The other side of each of these small ridges was a barren, rocky cliff, with a talus pile below, that clearly showed the distinct tilt of the rock strata, leaning toward the channel.

Other walks have been more productive of wildlife. My walking companions and I have found very large canid tracks in more than one location. These tracks were about five inches across, from outer toe to inner toe. Barring a return of the Hound of the Baskervilles, they have to be those of wolves. Happy thought! In a meadow near the Crow Point or Boy Scout trail, we found deer tracks of two sizes—maybe a doe with a late fawn, or a doe with an attendant buck. Vole tunnels in the grass along Eagle River were exposed as the snow melted, and led to small digs where the voles had eaten the roots of chocolate lily (aka rice root), often leaving some of the small bulblets (“rice grains”) scattered in the holes as well as the remains of earlier, well digested dinners.

vole-nibble-frit-and-scat
Vole nibble, Fritillaria bulblets, and vole scat. Photo by Katherine Hocker

We are lucky to live in a place that often offers great views over the landscape or over the seascape, into the distance, and many of us enjoy that. For me, however, the place truly comes alive when I concentrate on what lots of other folks would dismiss as ‘boring details’—seeing the little things. I revel in the little stories in the snow (or mud), the small signs of animal activity, sorting out the distinctions between the winter buds of different shrubs, watching a nuthatch work over the bark of a tree trunk. I loved watching a young porcupine demolish the plywood that reinforced a gate, even as dozens of humans hovered about, or a mother bear trying to keep track of three cubs while she foraged. This sort of fun is enriched by sharing with an interested companion or two, asking and sometimes answering questions.

Here are some very small observations and questions from recent winter walks near the lower ski loop at Eaglecrest. We found a tall snag with at least ten woodpecker cavities, which must have been excavated over many years. What made that particular snag so popular? In some of the meadows, the husks of crowberries held onto the stem but the seeds had been removed. ?by mice? There were quite a few remaining bog cranberries lying on the sphagnum moss, unharvested by any creature, so the seeds had not been dispersed. Will some lucky bird find them in early spring? The seed capsules of bog laurel and Labrador tea held their seeds tight, but the capsules of rusty menziesia were empty. Why the difference? We found well-worn squirrel highways running from one burrow to another. Does one squirrel, moving so predictably over the same terrain, live long enough to make a highway, or are several generations of squirrels using these routes?

That’s a tiny sample of the kinds of things we note and discuss as we wander about the forest and meadows. Another interesting exercise is to define a rather small area, maybe ten feet square, or twenty feet square, or whatever (some observers choose a one meter square!), and study it intently to see as many little stories as possible. Or just find a spot to sit for a while, on repeated occasions (for instance, daily or weekly), to register whatever happens there. It can be quite surprising!

Some folks find such proceedings unutterably boring and totally ignorable. It’s not for everyone! But I think that once one starts to see some of the details, it brings perceptions of our rainforest to the parts of our brains that think, consider, and imagine. Then the rainforest environments become more than part of the scenery.

Gastineau Channel

abundance of life along Juneau’s busy waterway

In late April and early May, Gastineau Channel is notable for the large aggregations of scoters. They raft up in hundreds and thousands at the mouths of Gold Creek and Sheep Creek. Most are surf scoters, whose males are distinguished by the white patches on the heads. Less common are the white-winged scoters, whose white wing patches are best seen when the wings are spread. Only careful inspection would tell if there are a few black scoters mixed in the flocks.

surf-scoters-in-the-channel-by-bob-armstrong
Surf scoters in Gastineau Channel. Photo by Bob Armstrong

Scoters are chunky, heavy-bodied sea ducks that winter along the coast. Those that winter to the south of us migrate northward in spring, often stopping to refuel in our area, toward their nesting grounds in the Interior. Canadian researchers have found a tendency for scoter migrations to follow the timing of herring spawning, which is generally later on more northerly coasts. Herring spawn is a favorite food of scoters.

On a low-tide morning in early May, a couple of friends and I walked down the beach on Douglas Island to Ready Bullion Creek. We went to see if dippers occupied their usual territory on the lower part of the creek. And yes, they were there, but they seemed to be nesting in a new site. The new place is one that for several years I thought would be ideal for them, but they had preferred to nest either down close to the intertidal or well upstream in a very narrow canyon. This time the nest site is between the former sites, on a cliff next to a nice waterfall and above a beautiful pool. (I finally got it right!)

As always, there were interesting things to be seen along the beach: two eagles with locked talons, spinning downward and breaking off just before crashing into the beach logs; a couple of migrating golden-crowned sparrows in the brush above the beach, on their way to the Interior and the subalpine habitats around here; male cottonwood trees starting to flower; a greater yellowlegs standing in the shallows; a pair of hooded mergansers flying by.

Small flocks of Barrow’s goldeneye cruised slowly along, in some cases in the company of a few pairs of harlequin ducks. The goldeneyes nest mostly in the Interior, but sometimes they nest in coastal areas—and at least occasionally in the Dredge Lake area. The harlequin females will go up along the coastal streams to nest, and (with any luck) they’ll bring flotillas of ducklings down to the sea later in summer.

The beach was covered with strange little tracks, which we deduced were those of crabs scuttling to and fro. A raven had marched in a straight line for many yards, and a deer had run down the sand. In one area, numerous holes in the sand, many of the surrounded by a tiny turret of slender, cylindrical fecal castings, may have indicated a population of some kind of worm (my ignorance is showing!).

The most interesting part of the beach was a shallow bight whose shore was densely occupied by sea stars. Many of the stars were steeply humped up over cockles or mussels (alive, alive oh!), having breakfast. They will also eat chitons, sea squirts, and limpets; the escape reaction of limpets is worth trying to see – they try to avoid the attacking star by ‘galloping’ away at Olympic speeds (relatively speaking, considering that they lack legs…). We noticed that quite a high proportion of the common five-armed star had only three or four arms, having lost the others to a predator (gulls, king crabs, other stars). Sea stars can regenerate lost arms, in time, but I wonder if there is a loss of efficiency in opening mussels or clams when there are fewer arms to pull open the shells. One sea star had a supernumerary arm, apparently regenerated from the side of a normal arm.

These sea stars displayed a remarkable array of colors—bright orange, dull orange, gray, brown with blue highlights, purple, brown with black bands across the arms, brown with dark blotches (like a rattlesnake, said a friend). It is highly unusual for any species to show such a diversity of colors. In the case of sea stars, it may be due, at least in part, to what they have been eating. And that may explain why an individual star can, reportedly, change color during its lifetime, and why a regenerating arm can be a different color that the rest of the star. A study of another species of sea star showed that diet had a big effect on the color of the star, although other factors must also be involved. I wonder if color has any effect on the risk of predation!

Shore pines

adaptations and interactions

shore-pine

 

On a recent hike, I spotted a tall pine tree with just one living, vigorous branch, which was served by a narrow strip of bark winding up the otherwise naked trunk. Refusing to die, so to speak, although perhaps no longer able to reproduce. That tree prompted me to think about our pine trees—but first, let’s put them in a broader context.

About forty-two species of pine are native to North America, but there is only one in Southeast. That one species is called shore pine, which is a coastal variant of the wide-ranging lodgepole pine. (The Interior variant of lodgepole is found near Haines and Skagway, as well as in the Yukon and down the Rockies.)

Among the North American species of pine, there is a fascinating diversity of cones and seeds. Cones of some species weigh over two pounds, more than five hundred times the smallest. Seeds of most species (including lodgepole pine) have well-developed wings, so they can disperse on the wind when the cone opens. Small seeds, weighing less than about ninety milligrams (less than a sunflower kernel), are generally wind-dispersed, but large seeds are dependent on animals for transportation. Some large-seeded species are dispersed by jays and nutcrackers that collect the seeds and cache them for winter food (but fail to retrieve them all); the eaten seeds are the price the tree pays to get the remaining seeds dispersed. Other large seeds may fall to the ground where rodents gather and cache them.

Some cones are heavily armored, with thick, tough scales, and sometimes with sharp spines on the scales as well; others have small, thin, rather flexible scales. Armored cones may defend the seeds against enemies, such as seed predators, insects, or drought. Spines on the scales are best developed in species whose cones open spontaneously; they deter some seed predators. For example, research has shown that spines hinder perching and probing by crossbills. Some types of red crossbills are specially adapted (by bill size and structure) to feed on pines, even specifically on lodgepole pines, but even these find the spines somewhat difficult to handle.

There is much variation in patterns of cone opening. Some species open their cones spontaneously, when the seeds are mature, although the opening may be spread over several months. In other species, including lodgepole pine, the scales of the cone may be glued shut with resin and a tree may simultaneously bear cones from many different years; all the seeds are stored in the cones, sometimes for decades. Cones with resin-sealed scales are termed ‘serotinous’ (from the Latin for ‘coming late’, referring here to the delayed cone opening). Serotiny is generally most prevalent in areas where forest fires – especially ground fires—are relatively common (perhaps every one to two hundred years in a given area). The heat from a ground fire opens serotinous cones, and a little later the accumulated seeds fall onto the burn, where they can germinate and grow with little competition, creating dense stands of young lodgepoles.

Lodgepole pines typically produce a good cone crop annually, in contrast to spruce, hemlock, and some other pines. The reliable availability of lodgepole pine seeds contributes to the stability of the populations of their seed predators, including red squirrels and crossbills.

Across most of the range of lodgepole pines, red squirrels are the main seed predator. The squirrels attack cones at the proximal or butt end, near the branch (in contrast to crossbills, which attack the cone at the distal end, away from the branch). Squirrels cut the cone from the branch and then start peeling back the scales. The proximal scales are bigger and tougher than the others and often bear no seeds, so they slow the harvest rate for the squirrels, and squirrels tend to favor cones with softer scales. For cones of similar size, a squirrel has to peel off the same number of sterile scales from few-seeded and many-seeded cones, so clearly the many-seeded cones are more worthwhile. The squirrels are able, by trial and error, to select cones from trees that have high numbers of seeds per cone.

Squirrels have caused lodgepoles to evolve various means of reducing the rate of seed predation. For example, lodgepole pine cones in areas with red squirrels tend to be wide at the base and sit very close to the branch. They often grow in whorls of two to five cones, all with their wide proximal ends close to the branch and each other. These traits all make it hard for squirrel to detach the cones from the branch. In turn, red squirrels may have evolved stronger bites, but the effect of lodgepoles on squirrels would be less than that of squirrels on lodgepole because squirrels exploit many different kinds of cones.

Now the fun begins, when we consider some more complex interactions!

–Red squirrels are absent from several small mountain ranges where lodgepole pines grow. In these places, almost all lodgepole cones are serotinous (fire-adapted). In contrast, where the squirrels are present, a smaller (but variable) proportion of the cones are serotinous. Retaining closed cones on a tree for many years means that those cones are exposed to squirrel predation for all those years. So serotiny has some disadvantages in such places; squirrels select against serotiny. As a result, in these locations, fewer seeds are released when exposed to fire, the density of seedlings is lower, and plant community dynamics there differ from the dynamics in areas where serotiny is the rule.

–In isolated mountain ranges where red squirrels are absent, resident crossbills are the main predispersal seed predators. Lodgepole pine cones there have larger and thicker distal scales than they do in places where squirrels are present. This makes it harder for crossbills to extract seeds. But the local crossbills have evolved deeper, more decurved bills, and concomitantly stronger bites, to counter these seed defenses. The stronger bills select for yet tougher scales, which in turn select for stronger bills. The absence of squirrels highlights the coevolutionary ‘arms race’ between cones and crossbills.

Where does this leave our local shore pines? Their cones are not serotinous and forest fires are rare in Southeast. Serotiny is reported to be more common in pines growing closer to the Interior, however.

Shore pines vary greatly in size, from scrubby, slow-growing dwarfs in muskegs (and other relatively infertile sites) to full-size trees around the muskeg edges. They need a lot of light and cannot grow in deep forest, but apparently they don’t do very well in soggy conditions. Lodgepole pine is capable of producing cones at age four or five years, in good conditions. The dwarfed shore pines in our muskegs can produce small cone crops, but the trees are likely to be very old, because they grow so slowly in that habitat.

So cone crops are presumably better on the bigger trees around the edges of muskegs, but there are fewer pine trees where the spruce/hemlock forest begins, and therefore presumably rather few pine cones overall.

That is probably why we don’t have red crossbills that are adapted to using shore pine as a food source; instead we have mostly hemlock-adapted crossbills and a few spruce crossbills. It is possible that some lodgepole pine-adapted crossbills might pass through occasionally, but because lodgepoles tend to produce good cone crops annually, the lodgepole-adapted crossbills are apparently less nomadic than others.

I do not know to what extent our red squirrels forage on shore pine seeds. I often see middens of spruce cone scales and cores, and spruce is clearly the squirrels’ main seed source. We occasionally see small piles of squirrel-harvested hemlock cones, which offer fewer calories per cone than spruce. But none of my naturalist friends reports signs of squirrel foraging on shore pine. I wonder if squirrels use pine more often in years when other kinds of cones are few, or if the squirrel population just crashes—both outcomes have been observed in southern British Columbia. So here is another little question to be answered, perhaps, by further observation.

In early March, on a small muskeg exploration, we found shore pines with next summer’s male cones and new female cones, still very small and tight. Pines are rather strange, in that pollination takes place in one year, but the cones do not develop and the ovules aren’t even fertilized until the next year. In the second year, the seeds and cones develop to full size. So the small cones we saw originated last year, fertilization will happen this spring, and the cones will mature this summer. I have not found an hypothesis explaining why pine cones take two years to develop or why fertilization is so much later than pollination. One more little mystery!

January frost and snow

explorations in Hilda Meadows

A bright, cold day—just right for a little exploration. A friend and I headed for Hilda meadows: up Trickster (not groomed), onto the groomed upper cross-country ski loop, over the snow bridge on the creek, and through some brush. We found a tiny patch of sun just in time for ‘elevenses’. Tiny indeed, and short-lived; the sun soon rolled around behind the ridge that is the Douglas Island backbone, and all was shady again.

Our perambulations revealed a wealth of animal tracks. The snow was a bit crunchy but not too hard for good tracking. Peripatetic porcupines had trekked long distances over meadows and into the woods. Most of their tracks were quite small, suggesting that these little fellows had been born just last spring. We noticed the one of them toed out more than others and so was individually recognizable.

There were a few squirrel and hare tracks, but not as many as some other times, a possible marten track, one ptarmigan had snooped around some blueberry bushes, and several weasel tracks. Short-tailed weasels or ermine had left evidence of their passing—across the open snow and down under logs and brush and back out again. Then, luckily, we chanced to see, out of the corners of our eyes, a moving blur, which briefly vanished under a stump and peeked out as a pair of beady black eyes on a small white face. The beastie itself! It scooted over to a log and peeked out again. Watching carefully, it apparently decided we were not much of a threat and bounded leisurely off. Ermine are more often tracked than seen, in my experience, so this was great fun. We were interested to observe that its fur was, in fact, not white as snow, but rather yellowish, so it stood out against a truly white background. Had the fur been stained by tannins (which turn many of our streams brownish) in wet moss?

We found a few examples of dead wood with frosty ‘fur’, a less spectacular version of what I reported a week or two ago. On that previous walkabout, there were wonderful sheets of silk-like strands nicely waved; any professional hair-dresser could have been proud of the result. I have recently learned that this phenomenon is actually called ‘hair ice’! The hairs are extremely fine: only about a one-hundredth of a millimeter thick, but they can grow to many centimeters in length. The process is roughly like this: As the water at the surface of the decaying wood freezes, more water is pulled from the surrounding wood, and it pushes out threads of ice from pores on the wood surface. The geometry of the openings of the pores in the wood influences the shape and direction of the hairs.

Somehow, a wood-decay fungus is directly involved, as was suspected a hundred years ago by Wegener (of continental-drift fame). Experimental elimination of the fungus by application of fungicide or heat totally prevents the formation of hair ice. Recent studies in Europe revealed that one particular winter-active fungus (Exidiopsis effusa) is consistently involved in the development of hair ice on a variety of broad-leaved trees. Filaments (technically, hyphae) of the fungus grow along the fluid-transporting vessels and rays of the wood. The fungus digests lignin, which makes wood hard, and also takes up tannins from the decaying wood. So far, so good. But exactly what the fungus does in the formation of hair ice is still a mystery. The decomposed lignin and tannins may provide a ‘crystallization nucleus’ that starts the formation of ice at the wood surface, or they might prevent the tiny ice crystals of the hair ice from recrystallizing into large crystals. And somehow the fungus might help determine the shape of the hair ice. Much remains to be learned!

I have not yet learned if that particular fungus occurs in Alaska, but we do have related species. And we certainly have hair ice. So another chapter of the story is waiting to be written.

Tracking at Eaglecrest

the usual suspects, plus a wandering otter

Eaglecrest was open, because it was spring break for the schools. So two snowshoers crept up the very edge of the groomed slope in order to (try to) stay out of the way of all the fearless little zoomers who were out to enjoy their holiday at top speed. A few of them apparently also enjoyed lunging over the edge of the groomed slope and plunging over drifts into the woods, so we kept a sharp eye out in case one came our way. Eventually we made it to the top of the slope and the upper cross-country loop, where things were calmer.

On this day we found many kinds of animal tracks—all the usual suspects, including red squirrels, snowshoe hares, weasel, mouse, ptarmigan, and peripatetic porcupines. Things got more interesting when we left the upper loop at its far end to visit Hilda Meadows. Just as we entered the first meadow, we encountered the distinctive and recent track of an otter, who had taken advantage of every little downslope to slide over the snow, leaving a smooth groove behind. This was an otter on a mission; it headed right down along Hilda Creek, which was mostly still buried in snow, into the steep canyon.

Not wanting to deal with the canyon, we were happily distracted by another set of tracks. Our best guess was that this creature was a coyote: fairly small dog-like footprints, all in a straight line. In the woods just above the string of small meadows, this trail paralleled Hilda Creek. The animal, like the otter, had a destination—with scarcely a deviation to sniff out a possible ptarmigan roost or to cross the path of a snowshoe hare, it bore straight down the valley. We’d lose the trail, sometimes, in the crusty snow under the trees, but we could always pick it up again in the next open space where the snow was softer. When the animal trotted down toward Hilda Point on the back side of Douglas, we settled for lunch in the sun.

On the way back uphill, we picked up the otter’s trail again where we first had found it, and back-tracked it along the creek. Near the top of the hill, we found that the otter had forsaken the creek in order to travel just inside the edge of the woods at a slight distance from the ski trail. When we reached the divide that separates Hilda Creek from the Fish Creek drainage (a swampy meadow in summer but now deeply buried in snow), we found the beginning of the otter’s trail. A hole in the snow led down to the very beginning of Hilda Creek, and the otter had emerged from that hole. So it must have slithered under the snow from the Fish Creek side, and presumably came up the Fish Creek drainage in its one-way journey. (And by the way, this is very near the spot where we found beaver tracks last month.)

We speculated that this might have been a male in search of a potential mate. Male otters range over many miles of stream and coastline and commonly overlap the ranges of several females. Mating is reported to occur usually in May (perhaps earlier in some years and some places), but the young are not born until the following winter or spring, because the embryo is not implanted in the uterus until long after mating and fertilization of the eggs. Delayed implantation is common among members of the weasel family. But it’s an interesting question: why do they do this!?

Sheep Creek Valley

trailside discoveries and memories of field work

I go up into Sheep Creek Valley several times a year; it’s one of my favorite places in Juneau. I was there in mid November with Parks and Rec hikers, and we spotted several things of interest. It had snowed recently, so tracking was good. We found tracks of squirrel, deer, mountain goat, a possible weasel, a large canid that could have been a wolf or just a big dog, and lots of porcupine tracks. Two porcupines scuttled off into the brush as we walked by.

A big conifer tree had a large squirrel midden around its base; discarded cone scales and cores covered many square yards. The main cache of full cones was underground, but this red squirrel was not content with that—it had also wedged cones into every available space between the roots and in grooves of the trunk.

We found a beautiful orange and yellow fungus growing on a dead branch. It is a type of jelly fungus, possibly the one called “witches’ butter”.

Some of the more enterprising hikers went up the slope at the back of the valley, far enough that they were wading in thigh-deep snow. Other, less energetic perhaps, were content to perch at streamside for a relaxed lunch break. The creek was running crystal clear and wide open, so we had hopes that a dipper might show up. Indeed, one did, prospecting for aquatic insects along the edge of the water and moving quickly upstream.

Sheep Creek Valley is among the first places I worked when I came to Juneau over twenty years ago. My first big project was to census nesting birds in various habitats; there seemed to be no previous studies of breeding bird communities that would provide an estimate of avian diversity and abundance in different habitats around here—very basic information for future ecological studies.

So for several years, in spring and summer, my field techs and I studied bird communities in Sheep Creek Valley and elsewhere in Juneau. We counted birds, using a standard protocol, by sight and by songs and calls. We found that this valley has a very rich community of nesting birds, arguably the richest one in our area. For example, we counted several kinds of warblers, sparrows, and thrushes—more kinds than in the spruce-hemlock forest.

Along with the standard censuses by sight and sound, we regularly mist-netted birds in the understory. Our black nylon nests were twelve meters long, and we would set up an array of about ten nets in various places. Then we’d walk the array of nets every hour or so, extract and weigh the birds, and release them. Among other things, the net captures helped us detect birds that were quiet and secretive.

There were a few bears in the valley. Occasionally, we would glance up as we extracted a bird from a net and see a calm bear sitting near the end of the net and observing all of our actions! They didn’t seem to have designs on us or on the birds; apparently they were simply curious.

Our other main activity was nest-searching. This is hard work and lots of fun, rather like a continual treasure hunt. By following a bird for a while, often on several occasions, eventually one deduces the approximate nest location, and then careful searching reveals a nest. It often takes several hours of detective work, perhaps over several days, to locate a nest this way. Once a nest was found, we monitored its progress, from incubation of eggs to care of nestlings to fledging—or until the nest failed. Then, for each species, we could calculate the percentage of nests that successfully produced young. For example, about sixty-five percent of yellow warbler nests were successful but only about thirty percent of robin nests and roughly twenty-five percent of fox sparrow nests were successful.

A principal cause of nest failure was predation on eggs or chicks. By installing small cameras that were triggered by removal of an egg, for instance, we learned that predators include Steller’s Jays, red squirrels, mice, and even shrews (see accompanying photo). But Sheep Creek had fewer egg and chick predators than conifer forest.

All of that work required us to begin at dawn, because bird activity is generally greatest early in the morning. The days are wonderfully long in spring and summer, so that meant we started work by three-thirty or so (and had to get up around two a.m., to get to the study sites; this was not so wonderful!). Nevertheless, I look back on those days with much pleasure (perhaps especially because I no longer have to crawl out of bed at crazy hours).

Stories in the snow

a snowy ramble reveals winter action

I love to go a-wandering along a snowy trail, looking for signs left by others who’ve been out on their business of living. A recent prolonged cold spell had kept the snow soft, preserving evidence of a very busy wildlife community along a local creek.

Mink tracks rambled along the creek-side, dipping down to the stream and curving up into the forest. The footprints were bigger than those of a second mink that traveled part of the same route, so my naturalist friend and I guessed that the first mink was a male. His trackway led a long way upstream on one side of the creek and seemed to circle back down on the other side—at least the footprints were the same size there. This might have been a male patrolling his territory.

Everywhere, we found the delicate, stitchery trackways of small rodents. According to the books at hand, mice are likely to drag their long tails, flipping them to the side as a counter-balance during sharp turns, but voles don’t usually show tail-drag marks. If that’s right, we had both mice and voles, especially on one side of the creek. The tiny trackways of shrews were less numerous.

Snowshoe hares had been busy, especially on the other side of the creek. Trackways led up to the streambank, then away, then back to creekside, then away. It was as if the hares wanted to cross the fragile ice but, lacking the nerve to do so, just dithered along the bank.

A bird had hopped about extensively in and out of some brushy areas. The tracks seemed too small to be those of a junco. Then we found wing-prints where the bird had flitted a short distance to a new site, and the length of the wing was clearly too long to belong to a junco. My guess was possibly a varied thrush, some of which overwinter here.

The only actual bird we saw was a brown creeper, hitching its way up a tree trunk and flying down to go up the next tree—their typical foraging pattern as they search for tiny bugs in the bark. According to the literature, creepers commonly concentrate their efforts on trees with ridged bark, the deeper the ridges the better; this kind of bark harbors more insects than smoother bark.

A few deer tracks, both large and small, appeared as we walked along. But there was much less deer traffic here than, say, in Gastineau Meadows, where peripatetic deer had cruised all over the place.

My friend called to me: Come look at this! I saw a shallow groove in the snow on the streambank and, without thinking, said: Oh, a shrew trail. Look again, said my friend. Ah—there’s a faint yellow stain at the bottom of the groove. And here, where I had casually supposed my ’shrew’ had dived under the snow, was—not a burrow at all, but just a deep dimple. My friend, who is smarter than I am, said: I think a bird, maybe a kingfisher, perched on that branch near the edge of the stream and projectile-defecated a jet of hot poop, melting the groove in the snow. So we said: Well, if that’s so, then in the dimple at the end of groove there should be a little wad of solid waste. And yes, indeed there was! Good detective work, friend!

A final little treasure on this walk was a dead red alder that sported a beautiful array of conks (or shelf-fungi). The living conks all had a slightly soft pile of white stuff at their lower edges. This stuff had occasionally smeared sideways over the bark, showing that it had been soft when the temperatures were above freezing. What is this stuff?

Phellinus-conks-kathy
Phellinus conks. Photo by Katherine Hocker

I took a sample to a local forest pathologist, who put it under his microscope. He said that the white material was certainly fungal mycelium (the technical word for the mass of filaments that grow through the wood before producing the spore-bearing conk). However, without DNA work, there’s no way to know if it belongs to a parasitic fungus growing on the conk or to the conk species itself, because this kind of conk (of the genus Phellinus) often grows some of its own filaments right down through the conk itself. So we ended our walk with one more mystery.

Hard snow

allows curious naturalists to extend their range

Hard snow in late January and early February made it easy to cruise around the forest on or off the regular trails. One could walk up the Thunder Mountain trail from DOT over the top of the nasty mudholes or prance without skis or snowshoes from Spaulding Meadow to the John Muir cabin. The low temperatures turned the snow to the hardness of concrete, in most places, so we could amble at will on our little explorations.

Well, in most places, yes. Except for the spot where the snow gave way completely and nearly pitched me into the adjacent river. One leg suddenly dropped into a hole, over knee deep, putting me right off balance. I was saved by a convenient, friendly alder that reached out a small branch in the nick of time.

We were walking along the lower part of the Herbert River, near its junction with Eagle River. The floodplain here is eroding badly and soon the Herbert will be shorter, joining the Eagle some distance upstream from the present confluence. Large trees have recently toppled into the water and lie waiting for spring floods to carry them toward the sea.

The fallen trees left steep cut-banks where the root masses had parted company with the floodplain. This exposed several horizontal layers of sediments of differing colors and textures: thin rust-colored layers of slightly coarser material were interspersed with wider, gray layers of very fine silt. These tell a story of variations in the flow of the river as the flood plain was built up. Roots had grown down through the layers, and the rust-color seemed to have followed along the course of the roots, perhaps leached by rain percolating downward and seeking the path of least resistance. Farther upstream, one can still see old river channels, now forested, where the river meandered before cutting its present channel. A lot of history is written in this landscape, for those who can read it.

Our wanderings frequently crossed those of peripatetic porcupines that had left their tracks when the snow was soft. There was evidence everywhere of porcupine lunches—spruce trunks with great gaps in the bark and porc-size tooth marks on the wood, neatly clipped spruce twigs dropped from the trees with the needles reduced to short stubs, even elderberry shrubs with gnawed-off shoots (despite their rank smell; apparently porcupines don’t care!).

Mink had scampered back and forth from forest edge to river, leaving numerous trackways now preserved in the crusty snow. Otter scat at the edge of the water showed the remains of a fish dinner. Of course, red squirrels had left their customary little piles of scales from alder cones and spruce cones as they extracted the seeds.

Another exploratory foray took us to a well-frozen wetland. As we meandered here and there, we noticed occasional beaver cuttings. Low-growing hemlock branches and small hemlock trees had been gnawed off and removed. Beaver teeth had scraped sizable patches of bark from standing hemlocks. A few shore pines and alders had been harvested, but hemlock was the clear favorite even though alders were quite abundant. This was interesting, because conifers are usually low-ranking choices for beavers. Alders are not a top choice either but are used in some regions. Their favorite trees are typically aspens, cottonwoods and willows, but these were not available here.

hemlock-midden-beaver-ck-KMH-Feb-2014
A hemlock midden. Photo by Katherine Hocker

We know that our local beavers sometimes cut hemlocks for use in construction, because we often see a branch or two incorporated in a dam. But the consistent use of hemlock for food seems unusual. There may be times of year when hemlock is more nutritious and palatable than at other seasons; such seasonal variation has been reported for pines and, accordingly, beavers in certain regions use pine seasonally. But why prefer hemlock to alder? As usual, we end up with questions!

The beaver lodge in this wetland did not have a winter cache of twigs and branches in front of it. But we found a midden a short distance away, where uneaten hemlock twigs had been removed from branches and stacked up in a pile, mixed with the de-barked branches. It is unusual, in our experience, to find accumulated remains of beaver lunches in middens like this one.

Snow!

a heron in the forest, a frozen feast, and raven excavations

The first halfway decent snowfall in mid November drew me out to look for animal tracks and anything else of interest. I went with a friend to the forested banks of the lower reaches of Eagle and Herbert rivers. Deer, both big and small, had wandered extensively throughout the area. Mink had a regular route along the top of one river bank. Porcupines had been out before the snow stopped falling, but squirrels left very fresh prints. Just as we were commenting on the lack of bird tracks, we happened upon some clear prints left by a heron strolling through the forest.

Then we heard a ruckus made by some squabbling ravens, over on a sandbar across the river. We approached quietly, with several trees (and the river) between us and the gang of ravens, but they spotted us immediately and took off. A number of magpies then moved in. The big attraction was the bony torso (spine and rib cage) of a deer, already well picked-over but still clearly worth serious attention. We settled down among the trees to watch.

We counted at least nine magpies; the precise number was not readily determined, because they were constantly flying to and fro: pecking and tugging briefly, then departing for a few minutes, and returning to grab another morsel. Were they caching these little bits of meat or just going off to eat each bit in peace? All those magpies seemed to be able to forage together without altercations (unlike the ravens); there apparently was room around and even inside the rib cage for them all.

A juvenile eagle arrived, briefly scattering the magpies, but they soon moved in again—on the side of the carcass away from the eagle. This was not very profitable feeding for the big bird, however, and it soon departed. Meanwhile, one or two ravens cruised by, or perched up in the spruces, occasionally hopping over the sand toward the bones but nervously taking off without feeding there again. Maybe nine magpies were too much for them, but I think they knew we were still there and did not like being watched.

A few days later, we had wonderful snow and lots of it. Spruces bore thick white blankets on drooping branches and alders bent almost to the ground under the heavy load. Rather than do the various tasks I was ‘supposed’ to do, I took off out the road to do a little exploring on snowshoes. ‘Twas the first time on ‘shoes this season, and it showed (sadly). Tracking was good, however: fresh deer trails, old otter slides leading from one patch of open water to another, not-so-old porcupine trails, deeper than the otters’ marks, a few squirrels, and a mink.

Two ravens were assiduously digging in the snow, in selected spots, tossing snow aside with their bills. Sometimes they dug down several inches, apparently getting very small, unidentifiable items. What could they be finding, and how did they know where to dig? I shared a few crumbs with them.

That lovely snow didn’t last, here near sea level. But I sure liked how it brightened up our short days!

First snows

some tracking discoveries and other observations

One of my favorite activities in winter is to go out looking for animal tracks in the snow. In early-mid November this year, the snow was perfect: not a lot of it, but soft enough to register animal passage and firm enough to hold the tracks’ shapes.

So, off to Eaglecrest I went, with two good friends who like these little explorations too. We found lots to look at. Porcupines had plodded in and out among the trees, in some cases making small highways of repeated use. A few red squirrels had ventured out of their burrows. A weasel had covered a lot of ground, bounding with shorter leaps when it went uphill. It investigated many a fallen log and stump in hopes of nice lunch. Weasels have to eat a lot, just to keep warm and feed their active metabolism.

Voles (or maybe mice – it’s often hard to tell which) had run over the snow from one grass tussock to another or from log to bush and back again. These were the most common tracks, often right out in the open meadows, where they might be easy marks for predators. But we saw no signs of lethal events.

Near the road, we found a spot where an indisputable mouse had hopped across. On either side of its trackway were marks of a tail flick. It couldn’t have been a vole, whose tails are very short, so it had to be a mouse. Why it had flipped its tail from side to side was not clear, however; we speculated that perhaps it was slightly off balance on the coarse cobbles at the edge of the road and used its tail to restore an even keel.

mouse-tracks-kmh
Photo by Katherine Hocker

We found a few lines of tiny tracks that were made by shrews. Emerging from one dime-sized hole, crossing over the snow to an equally minuscule hole, occasionally they tunneled just barely below the snow surface.

 

Every so often, we looked up instead of down and noted that quite a few trees had long-dead tops. No mystery there, given the howling gales that sometimes whip through this area. But none of the lower, lateral branches had grown upward to replace the missing tops. We’ve all seen conifers whose original ‘leader’ at the top of the tree has been killed but a lateral branch just below it has taken over as leader, creating a kink in the trunk. We puzzled over why this hadn’t happened on the trees in which the entire top was dead.

 

An answer might lie in the way that hormones control growth. Normally, the leader at the top of a conifer suppresses the growth of lower branches; this is known as apical dominance. But the effects of apical dominance diminish as the distance from the leader increases. So, perhaps, when the entire top of a tree is killed, the distance from the leader was so great that there was no dominance exerted on the remaining branches. Thus, the lower branches had not been suppressed and they did not respond to the loss of the tree top.

 

A few days later I walked out into the Mendenhall Glacier Recreation Area near Crystal Lake. Tracking was still good and there had been lots of activity. A porcupine had trundled across the ice on the lake, and a weasel (I think) had walked (not bounded) along the footpath. Squirrels and snowshoe hares had crossed the path.

 

The most interesting marks were made by a bird, whose wingspan exceeded five feet—surely an eagle. Its wing tips brushed the snow in several places around a patch where the snow had been disturbed. Here I could see some heavy-duty bird tracks, confirming the presences of an eagle. All around this area were raven tracks too. But there was no clue about what the eagle was after—unless it might have been a raven (eagles do capture ravens sometimes). It seemed unusual for an eagle to be hunting in a wooded area where the only open ground, where an eagle could spread its wings, was the path itself.

 

Lots of stories in the snow, so winter was off to a good start for me!