Short winter junkets

shoreline bird sightings, frost sculptures, and a startled grouse

One day after a nice little snowfall, I ambled out to Point Louisa in Auke Bay. The usual squads of harlequin ducks sallied out from the rocks or poked along the boulders. A few common and Barrow’s goldeneyes sailed by, some of the males half-heartedly beginning a courtship routine. A stray sea lion and a harbor porpoise swam by, looking for something tasty.

The best of the avian sightings was a little flock of black turnstones, calling as they flitted from one patch of rockweed to another. They only come to us in winter; they nest in western Alaska and winter all along the Pacific coast. These were not flipping little rocks—the behavior that gives them their name—but rather were merely pecking and poking for small invertebrates among the fronds of the rockweed. All of them were in winter plumage. But, unlike the photograph, most of them showed snazzy black crescents along the flank below the wing. These are created by small feathers that cover the bases of the inner flight feathers, and sometimes they hang down over the flanks. I have not been able to find out if the crescents show only in certain circumstances, and they are only illustrated in a few bird guides.

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Black turnstone. Photo by Bob Armstrong

The snow on the upper beach told stories. Shrews had made their narrow grooves as they ‘swam’ over the snow. A vole, heavier than a shrew, had waded through the snow from log to log, leaving a wider groove and a few footprints. An older set of tracks showed that a weasel had snooped into grassy tussocks and under logs, covering a good bit of ground in its search for dinner; it had missed both this shrew and the vole.

Up in the forest edge, a varied thrush prospected for anything edible and small, junco-size tracks hopped around under the brush.

A few days later, we entered a prolonged deep freeze. Everywhere I went, hoar frost decorated all the weeds and branches that were not under the forest canopy and spangled the ice wherever the snow had blown off. I strolled with friends around the rainforest loop near Eagle Beach State Park and ambled around in the Dredge Lakes area. The best bird we saw in the Dredge area was a rusty blackbird at the edge of the ice that fringed some open water; it was hunting for bugs in the water and found some. That’s exactly what dippers do in winter, and this bird fooled me for a minute.

I found it fascinating to observe the tremendous variety of forms the frost could take. I don’t know exactly what determines each variant and I probably don’t really want to know—much too complicated for me! But I can appreciate the wonderful forms anyhow. On a metal bridge we found flat, visually simple blades of frost, very different from the visually complex blades on many twigs. The more complex ones were as individually distinct as snowflakes are, and were composed of crystals oriented in many different ways. Some were flat and blade-like, but in some cases, the crystals took the form of tiny trees, with branches in all directions. Down on the bare ice, the spangles took the forms of flowers, or birds, or butterflies, each one originating from some little irregularity in the ice. A few days later, a light snowfall piled up on the ice-spangles, creating lumpy little muffins.

In the middle of December, after high winds had snapped off three snow-laden trees near my house and most of the wreckage had been cleared away, I plodded my way in to Tolch Rock and made the loop around by the gravel pit to the road. The trail was not obvious all along this route, but some long-legged, large-footed chap had plowed through the overhanging brush before the last snow fell, making it easy to find the trail once it was ‘misplaced.’ The only exciting thing was flushing a grouse, who took off with thunderous wings, and gave me a good jolt (question:.why don’t grouse turn white in winter, as ptarmigan do?) The snow was perfect for tracking critters, but very few small ones had been out. In contrast, the snowshoe hares had had a party! A mink had visited a tiny trickle that feeds into the smelly ditch near the entrance to the campground, and a mallard drake cruised by in that fetid ditch. Sometimes I even see dippers foraging in that sorry stream.

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There’s always something

finding little treasures on and off the trails

One day, as we walked along, a friend remarked: “You know, on every hike there’s always something spectacular or interesting or beautiful—some good memory to take home, in addition to enjoying some exercise and sociability.”

Although of course not everyone agrees on what is worth noting and remembering, on three hikes in late October and early November, I think there was consensus regarding the “take-homes.” All of these were flat, easy hikes, but all yielded some good thoughts.

Cowee Creek bridge to Echo Cove: Through the woods and meadow and along the beach, we noted little of special biological interest: not much sign of bears, no recent fish carcasses, very few birds. But it was spectacular—the sun was shining (!), and there was a fierce north wind screaming down Lynn Canal, stirring up huge waves and whipping veils of spray off the wave crests. In the background, the Chilkats gleamed with fresh snow.

Crow Point trail along Eagle River: We found lots of small things of interest. Many critters had left signs of their passing. There were scats of goose, bear, probable coyote and marten, and tracks of otter in the sand. A big crowd of crows was hanging out at a distant edge of the tide flats, occasionally flying up and dropping small items (?mussels?). We guessed that there must be a few rocks out there, if the crows were thinking to crack open some shells. Bears had been digging roots of wild parsnip and riceroot. Chum salmon skeletons had been spread around by high tides; they already had a coating of green algae.

There were small mysteries too. The B-B-size seed capsules of starflower were covered with a white ‘bloom’ and the contents looked like dirt. Could they be afflicted by a fungus? We saw squirrels extracting seeds from spruce cones and a flock of crossbills checking out the cones that remained on the trees. But all the cones we inspected had almost no seeds left. The red squirrel may be able to detect full cones by smell or heft, but how do crossbills know if a cone is well loaded with seeds? Trial and error?

The sun peeked out briefly, in time for our little picnic lunch. We were attended by a raven, who wouldn’t come down for treats, perhaps because we had a (well-behaved) dog with us. After we left, and turned back along the beach, the raven circled us with one of the treats in its bill, almost as if it was saying ‘Look, I got it!’ I don’t really imagine it was saying thank you. It’s more likely it was hoping for another ! Naturally, I provided.

Dredge Lake area: this was a mild day with very hazy sun and a few inches of fresh, wet snow on the ground. Our several attempts at some off-trail bushwhacking were thwarted by high water levels. But the soft snow recorded tracks of squirrels, hares, beavers, mink, an eagle, and perhaps an otter. As we ambled up the beach of Mendenhall Lake, the mists that hid the mountains gradually parted and, one by one, McGinnis, then Bullard, then Thunder showed themselves. The vista toward the glacier was indeed a beauty—if, as a friend commented, one has learned to love shades of gray and silver!

Even cruising down Egan Drive had some good moments, such as a flock of swans winging south. There was a family of swans near the Vanderbilt junction: two adults and three big, gray cygnets. A rare treat for me!

The next time we get one of those dismal, gloomy stretches, with slatting rain during the few hours of what passes for daylight, I’ll remember the good days and all the little treasures thereof.

Hilda Meadows

musings on winged seeds

Typical Juneau weather! We get a nice snowfall, for good skiing and snowshoeing, then it thaws and rains and makes the snow soggy. Then we get a hard freeze, so the footprints and postholes created by walkers during the thaw are frozen solid. After that happens, walking there is a misery of lurches and ankle-turnings. The popular Dredge Lake trails are a good example. Then the cycle starts over again—lovely snow, then rain…

Before the last rains, however, Parks and Rec hikers did manage to fit in one excellent junket to Hilda Meadows above Eaglecrest, on the one perfect day with good snow underfoot and more coming down all day. Some of us were on skis, others on snowshoes. There was enough firm snow that it was easy to find places to cross Hilda Creek on our way to the chain of meadows.

Critters had been active overnight, so here and there we saw tracks of hare, squirrel, and weasel, rapidly being covered with new snow. Trundling porcupines left numerous furrows as they wallowed in the fresh snow from tree to log to tree. One hiker inadvertently flushed a feeding ptarmigan, which flew complainingly off into the conifers. We all inspected its tracks; it had circled several small blueberry bushes, nibbling on buds.

The surface of the snow was dotted with wind-blown spruce or hemlock seeds. I wasn’t sure which kind they were, so I checked the forestry literature to see how to distinguish them. Western hemlock seeds are smaller, on average, than Sitka spruce seeds, but mountain hemlock seeds are larger. Foresters don’t usually measure individual seed weights; instead, they count the number of seeds per unit weight. So they estimate that there are 570 western hemlock seeds per gram, 400 Sitka spruce seeds per gram, and 250 mountain hemlock seeds per gram. (There are 28.35 grams per ounce, if you want to convert those numbers to the English system of weights and measures.)

spruce-and-hemlock-seeds-by-Hocker
Spruce (left) and hemlock (right). Photo by Katherine Hocker

I also collected some spruce and western hemlock cones and extracted the seeds. In general, spruce seeds look fatter and the wing seems a bit wider, but there is a lot of overlap in apparent size of the wing.

When seeds are released from cones, most of them land fairly close to the maternal tree. Many of the seeds that land near their mother or each other usually die, because seed predators focus on high densities of seeds. Or, if those seeds germinate, the crowded seedlings compete with each other, stunting growth and eventually causing mortality. Therefore, it is important to the tree’s reproductive success that some seeds disperse to greater distances. This can happen in a big wind or, as we saw on our way to Hilda, when fallen seeds are blown over the surface of the snow in a breeze.

The convenient name for the distribution of seeds around a parent tree is ‘seed shadow.’ The seed shadows of trees are difficult to measure, especially for far-traveling seeds, and most studies have ignored the ‘tail’ of tree seed shadows. With that limitation, a review of published studies of tree seed shadows suggests that Sitka spruce seeds may tend to fall closer to their parents than do western hemlock seeds.

It might be interesting to do a little experiment with our wind-dispersed trees (spruce, western or mountain hemlock, Sitka or red alder), all of which have winged seeds. Take seeds from ripe cones, an equal number of each species. One by one, drop the seeds from a standard height, letting them land on a clean surface. Mark the landing site of each seed. Then compare the average and maximum distances achieved by each species. Try it all again, in a breeze.

Are some wings better than others for carrying seeds away from a source? Does the ‘wing-loading’ of each kind of seed differ, and is that related to dispersal distance? (Wing-loading is the ratio of seed weight to area of wing.) Is the total weight of the seed-plus-wing important? How does the height of release or breeziness affect the outcome?

!Prospective Science Fair students take note!

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.