juneau – On the Trails in Juneau

Weather and wildlife in March

wild and windy walks in a season of transitions

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

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

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

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

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

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

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

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

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

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

Felt-leaf willow buds. Photo by Kerry Howard

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

Weather and wildlife in March

wild and windy walks in a season of transitions

Winter in Juneau

a little bit of this, a little bit of that

Winter is an odd time of year here. Sometimes it rains, seemingly forever; sometimes a low, gray cloud parks itself over us for days; sometimes it’s absurdly warm but at other times it’s quite cold and the little bit of wet snow on the ground turnsrock-hard. Even expert forecasters don’t always get it right. When we’re lucky, there’s a good fall of deep, soft snow that makes skiers smile.

One such good snowfall at the end of February sent me and a couple of friends out on snowshoes, plonking around the big meadow near the Eagle Valley Center. That meadow often offers a fine winter record of animal activity on the snow, but on this day we didn’t even see the usual squirrel and porcupine tracks. However, we did see three long shrew trails, way out in the open. The deep snow had a very light crust on top, just enough to support a shrew without much body drag. This was long-distance travel, over many meters—looking for what? Near the far end of the meadow, we spotted the tracks of a medium-size canid that had poked around under some conifer branches and gone off in another direction. Nowhere on our tour had we seen any doggy tracks associated with the quite fresh human boot tracks, so we cheerfully decided that a coyote had been there(maybe).

Bird observation in winter is just as variable as the weather. Sometimes we see quite a few loons, of two different species, but no luck (for me, anyway) this year. Snow buntings and Lapland longspurs show up on the wide, grassy meadows sometimes. Magpies arrive from the Interior, but this year I haven’t seen as many as usual. Pine grosbeaks come too, but I’ve seen none at all, so far. Nor have I seen the occasional slate-colored form of the junco, which comes from the Interior. And where are the siskins and the crossbills??

Favorite occasional winter arrivals are small flocks of the elegant Bohemian waxwings, which sometimes can be seen foraging on mountain ash fruits. They get part of their name from little red blobs of ‘wax’ on the tips of their secondary wing feathers; the red blobs are bigger on older birds and (along with other features) may influence mating success. They are obviously not strictly Bohemian at all, being distributed over both North America and Eurasia, nesting in boreal forest regions and moving somewhat south (including to Bohemia) for the winter. They feed largely on sugary fruits, with additions from insects especially in the breeding season, and sometimes buds, flowers, snails, or other oddments. There has been little intensive research into their ecology.

Unlike the ever-changing winter weather and the often-unpredictable winter bird populations, trees stand there all year round. But they do their own kinds of changing.

The leaves of deciduous trees avoid winter problems by dropping off the trees. But conifer needles face cold temperatures, sometimes wind, and lethal water shortages if the ground freezes. When the ground is thoroughly frozen, the needles receive no water and cannot conduct photosynthesis; then too much sunlight can be deadly, leading to the accumulation of free-radicals and other damaging particles. Needles have some built-in features that provide some protection, such as a waxy cuticle and a small surface area that conserve water and resin content that is resistant to cold. In addition, they may increase photo-protective carotenoids, and they have a lower metabolism at low temperatures and an ability to continue photosynthesis at a reduced level.

If, despite that first line of defense, ice crystals form in the cells, they can damage critical organelles inside the cell: the nucleus with genetic instructions, the mitochondria that control metabolism, the chloroplasts that house chlorophyll that captures light to initiate photosynthesis, and other miniscule particles that carry out normal procedures. The crystals also can ruin the cell membrane, exposing those organelles to damage and destroying the cells.

Activated by short day-length and cold temperatures, there’s a second line of defense at the cellular level: cells make some changes to reduce that potential damage. Cell membranes become more pliable, as saturated fatty acids are replaced by un-saturated fatty acids, which freeze at lower temperatures. Some cellular water is moved out of the cell to the interstitial space between cells where, if it freezes, the crystals cause less damage. Furthermore, as interstitial water freezes, it releases a tiny amount of heat, which may help keep the cellular fluids from freezing. Inside the cells, starches are converted to sugars, lowering the freezing point. Lipid concentrations may increase too, and there can be some particular proteins that resist freezing.

Come spring, with warming temperatures and longer days, if the cells remained undamaged, those cellular changes are reversed, restoring the cells to normal conditions. Metabolic rates rise to normal and photosynthesis is again conducted at the usual rates. That’s an impressive array of seasonal adjustment in a seemingly simple thing like a conifer needle.

February trails

snow at last, a winter fungus, and wetland sightings

January whined its way toward its end, with seemingly interminable days of warm rain—what a miserable excuse for a winter. And then—surprise!!—a starlit night, a nice day, lower temperatures, and then some lovely snow. A great way to end one month and begin the next one. Yes, of course, I had to shovel my deck and the berm left by the city plow, but a neighbor helped with the heavy part of the berm, and altogether the wonderful white stuff was well worth the labor.

So it was ‘Find the snowshoes and let’s go see what we can see.’Partway up the Eaglecrest road, no parking was readily available near the lower meadows, so we ended up plonking around the ungroomed lower loop. We found several deer trails, partly obscured by recent snow. Snowshoe hares had been out in the night. And there were several fresh tracks of squirrel and weasel (no doubt in its white winter coat). There were no little birds in the trees and no signs of porcupine or grouse, which was unusual up there. But it felt like winter was happening!

Early in February, after a good snowfall, I wandered down the east side of Mendenhall Lake on snowshoes, relearning an old route. The snow had covered all the animal tracks, if there had been any, and draped the small trees with heavy white shawls. Strangely, the fog created an eerie illusion that the big rock peninsula on the west side of the lake had somehow advanced, so that it now approached the beach on the east side. Reassuringly, when the fog lifted for a while, the peninsula was back in its usual place. The highlight of the walk was seeing dippers foraging in the lower reaches of Steep Creek, one working along the edge of the creek and a second one soon joining.

In mid February, more snow…replacing what the rains had wrecked. A friend and I went to the meadows by Peterson Creek on snowshoes; that’s a place where we’ve had good animal tracking sometimes. Off we went, but our stroll was curtailed by high water in the numerous sloughs; it hadn’t been cold enough to freeze them. So the walk was short, but we found squirrel tracks, bounding from creek-side to the trees, deer tracks out in the open, and a long trail of porcupine tracks wandering hither and thither. The creek was running high and no dippers in sight.

A few days later, during a little snowfall, we wandered over the Outer Point Rainforest Trail. Along the forest trail, a wren did not care to be watched and zipped speedily under some logs. Out on the water, a little group of goldeneye ducks cruised lazily along. The glaucous-winged gulls loafed on rocky points and a few of them floated quietly, heads tucked next to the body, looking totally relaxed. Just one bird was actively foraging– a small grebe made repeated dives.

On a rugged bedrock outcrop not far above the high tide line, a number of little potentilla plants flower in the summertime. On this February day, we expected to see only flattened brown leaves and decrepit seed stalks. But behold! There were ever-so-tiny green leaves peeping out from behind the protection of the old brown leaves!

In the Dredge Lakes area, another friend showed me a lovely colony of a spectacularly orange fungus, growing on an old cottonwood snag. This is Flammulina populicola or velvet shank, a gilled saprophyte that grows only on dead poplars and aspens. It has the unusual habit of fruiting and producing spores in the winter (hence an alternative common name of winter fungus). It has special ice-binding proteins that keep ice crystals from ripping its cell walls (the proteins are similar to those found in diatoms and bacteria that inhabit icy waters). The brilliant orange color is best developed in light environments; if it is growing in the dark, the fungus is whitish.

A little walk on the dike trail began in a light snowfall but—in true Juneau style—it soon changed to rain. There were throngs of geese grazing out on the flats near the open water, a scattering of goldeneyes and buffleheads in a lagoon near the trail, but no mallards. An odd lump moseying along the edge of a not-too-distant slough attracted my attention and, with binoculars, it turned into a killdeer. I’ve been told that it is not very unusual to see killdeer here and in the Fish Creek estuary across the channel in the winter, when other shorebirds have gone south.

Thanks to Jenifer Shapland for putting a name to the orange fungus.

Field notes

and the games we play with animal names

Most of my recent trail walks have produced little sign of wildlife activity. But on a stroll in the Dredge Lake area, I saw a river otter in a bit of open water near the inlet of the Holding Pond. It soon dove under the ice and came up near the outlet, where the creek flows out to the river. I’ve seen otters here in other winters too and suspect they come up from the river to see if there are any fish to be had, not staying long. And at Point Louisa, there are sometimes scoters, goldeneyes, buffleheads, harlequins.

Over on north Douglas, a tight little bunch of sea lions surged past the boat ramp. A friend and I cruised the Outer Point/Rainforest loops while falling snow quickly covered lots of squirrel tracks. There were a few fresh tracks of a small bird, perhaps a junco, in the snow at the edge of the meadow. A big vole or a mouse had bounded across a gap between clumps of grass on the upper beach, making a leap of about seven inches. Goldeneyes nibbled along the rocks at the edge of the water and, a bit offshore, a little bunch of harlequins dove. Back in the woods, a wren darted out from under a foot bridge into a brushy tangle and then under a big log, not to be seen again.

That little wren is known as the Pacific wren, but it used to be called the winter wren, part of a species that nests widely across North America (and in Eurasia too). But taxonomists got busy and decided that these were really three different species, so they split the old classification and assigned new names. Now there’s the Eurasian wren (Troglodytes troglodytes), the Pacific wren (T. pacificus) that nests along the Pacific coast and in the Pacific Northwest, and the winter wren (T. hiemalis) that nests in the northern part of the eastern U.S. and adjacent Canada—but with a long westward extension of the breeding range out to northern British Columbia, where it overlaps with the Pacific wren.

Most of us could not tell these North American species apart by sight, although the Pacific wren is somewhat darker. But the vocalizations are known to be different. Where the ranges overlap in B. C., males of different song types held territories next to each other. Furthermore, singers of the different songs have different genetics, different enough to justify splitting them into separate species. Now we need information on what the females are doing…selecting males that match their own type?

And the taxonomists may have fun with another bird, known to us as Steller’s jay. Bird-watchers have noted the existence of plumage variation in various parts of the species’ range: Coastal jays have short black crests, blue forehead streaks, no eyebrow mark. Interior jays are similar but have a white eyebrow mark. Rocky Mountain jays have a long black crest and white marks on forehead and eyebrow. (In addition, jays in Guatemala and southern Mexico have blue, not black, crests.)

Coastal Steller’s jay. Photo by Kerry Howard

Geneticists got to work on comparing the Rocky Mountain jays with the Coastal/Interior jays and found significant genetic differences. That pair of populations is at least as different genetically as other pairs that are now accepted as different species: for instance, alder and Traill’s flycatchers, red-breasted and red-naped sapsuckers, white-crowned and white-throated sparrows. Furthermore, the Rocky Mountain jays occupy areas with different vegetation, a different climatic regime, and probably had a different history during glacial times.

So the researchers suggested some new names, perhaps officially becoming names of separate species. The Rocky Mountain forms might be called the long-crested jay (or perhaps the long-crested Steller’s jay), while the coastal/interior forms might be called the blue-fronted jay (or the blue-fronted Steller’s jay). More distinctions probably lurk down the taxonomic road!

Why bother with such distinctions?

From a scholarly perspective: sometimes, when we compare two very similar things (in this case, species), we discover that some tiny, subtle difference is actually not subtle at all but has significant ramifications for ecology and behavior. These discoveries expand our understanding. Furthermore, if two populations are sufficiently different to rank as separate species, they are capable of evolving in different, independent, directions, acquiring new, distinctive traits. Discovering those new directions increases our understanding of the ecological system.

In directly practical matters, distinguishing related but separate species is a useful tool for conservation: population trends can be monitored separately, not obscured by whatever is happening in the whole taxonomic complex. In this era of massive declines in many populations, it is useful to know how each population is faring.

November

observations in snow, mist, rain, and sun

A good snowfall in early November drew us out to enjoy the brightened landscape and see what we could see. Before we got very far, we crossed the trail of a very small porcupine that had travelled for many yards as if it had a known destination despite its presumed lack of experience.

Our route of choice for this first wintry walk was the beach on the west side of Mendenhall Lake., which is walkable when the water level is low. Snow clung decoratively to alder twigs and cones (and built up huge cakes under my cleats). At the upper edge of the beach, we found two big ice-boulders, presumably rounded remnants of ice bergs cast up by the jokulhlaup a couple of weeks ago.

The creeks that come down to the west side of the lake were still open and flowing, although crossing them was easy. At one creek edge, a little plaza of ice had made a dining table for mink: There were scuffle marks, a few blood stains, and lots of mink tracks. Some small fish had made that mink happy.

Then the weather changed, temperatures rose, and the rains came, destroying the lovely snow. Fog settled down over the valleys and the channel, turning the visual world into shades of gray. From the east side of Mendenhall Lake, we could see lots of recent icebergs parked partway down the lake. The blue reflections from the denser ice were the only bright spots of color visible on the landscape. An eagle hunched down, just resting, on a high cliff not far from Nugget Falls. A great blue heron stood motionless in the shallows at the edge of the lake, presumably hoping a little fish would wander by. A gray bird on a gray lakeshore with a gray and white backdrop.

On my home pond, the ice cover thinned but still supported several mallards that gobble up seeds that fall from the overhead feeder. They often rest in open water just below the dam—maybe watching that feeder for signs that the little birds are shaking out some seeds. Then they slide over the dam and hustle out to the place where seeds fall. When that is cleaned up, they march up and down the pond, to the open water at the inlet and back to the fallen-seed place. As the inflow of the stream slowly melts a channel through the ice, the ducks swim along the edges of the channel, nibbling at the edge of the ice (perhaps some edible bits are there??).

Beavers in the Dredge Lake area had been quiet, but their activity resumed with the warmer weather. A Beaver Patrol trail-cam captured an adult beaver hauling branches out to its winter cache, taking time to nibble a twig, while an observant youngster watched closely. A half-culvert that had been ignored for many weeks was suddenly packed full of brush and weeds. Almost as soon as the Beaver Patrol removed all that stuff, by the next day the beavers had crammed the culvert full again. Usually, by mid-November, beaver activity has shut down for the winter, but not this year.

The Beaver Patrol team had a treat at the Holding Pond one day; a dipper was foraging by the outflow and did not want to leave; eventually it moved across the pond to a small inflow area and foraged in the shallows. I had not seen a dipper here for a long time, although in some previous winters I could find them here fairly frequently, when the water was at least partly ice-free.

A few days later, the skies were blue, and all that sunshine required a walk that took advantage of it, so we went to Eagle Beach State Rec Area. The brilliant sun was so low in the sky that shadows were extra-long—a small hill across the broad river cast a long shadow over the wide river and across the big meadow near the parking lot. The river had done more serious erosion of the bank by the big meadow. All the gulls were parked out on the farthest edges of the sand flats, at the water’s edge. No importunate ravens came to our picnic lunch on the beach, but the frost patterns were gorgeous. And a touch of sun-warming was welcome on a frosty day.

Walking out on the tide flats, we found lots of goose tracks and eventually saw a dozen geese resting on a distant sand bar. A big muddy channel was littered with thousands of horse clam shells; there are probably some live ones buried in that mud somewhere. In a very small muddy channel, mixed with some goose prints, there were recent tiny tracks of a shorebird (with three front toes and no hind toe), but the track-maker was not to be seen.

Late September notes

quiet trails, fall colors, and dragonfly migration

It’s been rather quiet along the trails in late September: here a pair of hermit thrushes, there a trio of varied thrushes, and a stray robin or two. Coho were milling about in Mendenhall Lake, rumpling the water surface. From the beach on the west side, I watched a seal or two making bigger rumples as they tried to grab a fish. I saw no coho going up the west-side streams, as they usually do, but they were going up Dredge Creek on the other side of the lake.

I met a dog-walking fellow who remarked on his enjoyment of the fall colors, as we looked at the golden cottonwoods, yellow willow leaves, and the red/pink/yellow leaves of highbush cranberry. Dwarf dogwood has been spectacularly red along some trails, with small spots of color from trailing raspberry and nagoons. Along the lakeshore trail, new willow-roses were developing, showing brilliant red on a background of still-mostly-green willow leaves. The midge larvae inside will emerge next spring, having fed on the inside of the gall, and face the world as adults.

Meanwhile, I was sent a link to an article in a Wisconsin newspaper about huge swarms of dragonflies headed south on their fall migration. Tens and maybe hundreds of thousands of dragonflies were on their way, attracting so much public attention that they even made it into the newspaper (and there are other migrating swarms, on the east coast, near the west coast, and in between). Several species had joined the swarm, but the great majority of them were green darners (Anax junius)—possibly my favorite dragon, very snazzy. The Latin name means June king—“king” perhaps because of its large size, with a wingspan of almost twelve centimeters, bigger than most other North American dragons. They typically breed in quiet waters of vernal pools and marshes, where the females lay their eggs on aquatic plants. These mighty predators are able to capture and eat other adult dragonflies, as well as many other insects. They range over most of North America, coast to coast, from southern Canada to Mexico, Hawaii, and beyond. They don’t get to Alaska except by accident of vagrant winds. But their regular migrations take them from the northern part of the range to the southern part in fall, and back again in spring.

Green darners are well-known for making long-distance migrations and we now know a little more about their fall travels. The advent of miniature radio transmitters, small enough to be glued onto a dragon’s back, allowed researchers to follow their progress for several days. The dragons made an average of about twelve kilometers per day, with stopover days for foraging in between the flight days. They took advantage of northerly winds, after a cool night or two, and typically flew with the wind, although they seldom flew on very windy days.

The swarms are apparently more common in fall than in spring. Swarms are composed of individuals from widespread areas, gathered together in fall to follow shorelines, ridgelines, and other landmarks. Individual dragons bore natural markers in the form of isotopes that could be identified to their approximate sources; natural isotopes of hydrogen, for instance, can have one, two, or three neutrons, changing their atomic mass (‘weight’). The proportion of hydrogen isotopes (in water, for example) varies geographically (e.g., latitudinally), and this is reflected in the body composition of the critters that grew up in different areas.

A simple version of green darner migration divides things into three generations. Generation #1 emerges in the south in February to May, flies north, where it breeds and dies. Generation #2 emerges from that breeding activity in the north, flies south to breed and die. Generation #3 are the offspring of fall migrants and do not migrate; these residents breed and die in the south and their offspring migrate north in spring.

But it’s not really quite that simple! Individuals in the green darner population of some places (data from two studies in the north) seem to be comprised of individuals with two different migratory patterns. A given population may have some adults emerging and breeding in summer, whose slowly growing larvae overwinter in the breeding pond, emerging the next summer to breed there as adults. Other individuals in the same pond are small larvae in early summer (whose parents were spring migrants); these grow quickly, with adults emerging and breeding in late summer and fall, and then disappearing on fall migration. This makes it seem that these northern populations contain both residents and migrants.

Studies of the population genetics have shown that green darners have not differentiated into distinguishable populations but rather exhibit widespread similarities, which indicates genetic mixing throughout the whole population. Spring migrants probably do not go back to where the previous generation of their parental lineage came from; they may settle to breed somewhere along the way. Their offspring therefore cannot be closely adapted to particular rearing conditions in various geographic areas. So researchers now consider the possibility that the life-history differences (resident vs migrant) may be flexible. Perhaps the early larvae decide which life history to take on the basis of some environmental trigger.

There is much to be learned about migratory strategies in green darners. What cues do the migrants use for orientation on the long flights? How do they decide where to settle and breed? Do the offspring of a given female actually embark on differing life histories, depending on circumstances? If life histories are flexible, what are the triggers that determine which alternative prevails? Will the relative frequencies of the two pathways change as the climate changes?

Beaver notes

winter activity by beavers and others

A spell of warm temperatures before the winter solstice let beavers continue stocking their caches with branches. Although adult beavers can live off stored fat for quite a while, young ones are still growing and need to eat. So a beaver family caches a nice pile of fresh branches not far from their lodge entrance. Here are excerpts from a Dredge Lake area trailcam video of a beaver systematically de-branching a little tree and toting away the branches for its cache. I noticed two uncommon things that this beaver did; readers might like to check the video and see if they can spot these two things. (**My two choices are given at the end of this essay; no peeking!).

The solstice came and went, but it will be a while before we can really sense the lengthening days. Meanwhile, a couple of days after the solstice, I wandered over to the Dredge Creek area. The recent deep freeze had covered the ponds with strong ice, shutting down beaver activity for a while. A snowfall had brightened the landscape and registered movements of small critters. I found a trail left by a shrew, making short bounds under a bush. Another shrew had trotted across an open space and under a log.

Bigger tracks were left by an otter moving up Dredge Creek. There was a little bit of open water just below the beaver dam we call Nemesis, and the otter had come up from under the ice of the Holding Pond, gone over the frozen splashes of the dam overflow and onto the frozen surface of Dredge Creek, disappearing upstream.

At the very end of the year, beavers at another lodge came out to work on their caches. Temperatures were absurdly mild, but snow had accumulated near the lodge.

Trail cam photo of a beaver exiting the lodge

While I’m thinking about beavers, I’ll take this opportunity to discuss them as carriers of disease. In a recent essay I mentioned tularemia, sometimes carried by beavers. But we hear more about another ailment, for which beavers are often blamed. Giardiasis is caused by Giardia, a one-celled protozoan that can infest the small intestine, causing diarrhea and other digestive distress in humans, cats, and dogs. There are several species of Giardia, specifically afflicting various kinds of animals (e.g., mice or birds or amphibians), but only one (commonly called G. lamblia) is known to parasitize humans as well as many other mammals. It seems that most of those mammals are asymptomatic carriers of Giardia; at least I found (so far) no reports of sickness except in humans, dogs, cats, and maybe pigs (all of which can also be asymptomatic carriers).

The life cycle of this parasite includes an active, reproductive phase (called a trophozoite), which multiplies in the airless intestine, and an inactive encysted phase. The disease is transmitted by the cysts, which are passed out of the digestive tract with feces (trophozoites may be excreted too, but they soon die). When another animal ingests fecal matter (directly or on vegetation, for example) or water with cysts, the cysts pass into the gut, where they open and release trophozoites, which feed and multiply rapidly. It can take up to two weeks for a new infection to produce symptoms.

Although the cysts can be passed from one animal to another by contact with fecal matter, they are more famously acquired from feces deposited in water. There can be thousands of cysts in one drop of water; they can persist for weeks and be taken up from water drops by swimmers or paddlers. The association with water, and thus with beavers, led to the affliction being called ‘beaver fever’. But that is totally unfair! At least in some areas, humans are the main transmitter of cysts, via improper disposal of sewage. Furthermore, muskrats, dogs, moose and deer, and many other mammals that defecate in or near water also contribute to the spread of the disease.

**Here are the uncommon activities that I noticed in the video. 1. One of the branches selected by the beaver appears to be dead—barkless, budless, and white. In another segment of video (not shown), a similar branch is also taken. No good for the food cache—beavers feed on the bark of living branches. Could they possibly be constructing something else? 2. This beaver held one branch in its mouth while chewing off a second one, and then dragged both branches off to the cache in one trip. The big space between the front, cutting, incisors and the grinding molars to the rear of the jaw is called a diastema. The lips can be closed behind the incisors when the beaver is chewing a branch off, keeping loose chips from going down its throat. This beaver, however, appears to hold the first branch in the diastema while gnawing at the second one.

Thanks to Jos Bakker for the trail cam photo and video.

Autumn arrives…

…gradually!

Fall is unofficially here, whatever the calendar says: fireweed has gone to seed, sending parachuted offspring into the breezes. Geese are numerous on the wetlands, with more arriving from time to time; more flocks are landing in the big meadow near the Boy Scout camp. Some male mallards are showing signs of developing their breeding plumage. Robins are flocking up and shorebirds have gone south. Cottonwood trees have a few golden leaves, which are released one by one to float gracefully to earth.

Most of the wildflowers (at sea level) have finished blooming. The tall stalks of cow parsnip stand sere and brown. Here and there I can find the very last flowers of lupine and beach pea, but yellow rattle and yarrow still have some fresh flowers, and yellow paintbrush looks good. Among the late bloomers are hemlock parsley and purple asters (not to be confused with the purple daisy, which usually blooms earlier at sea level). Marsh felwort is always late to appear.

The woods are showy with red berries: bunchberry, elderberry, baneberry, the native species of mountain ash, and devil’s club. It has been a good year for high-bush cranberry too; some of the flexible branches droop with the weight of fruit.

Here are a few observations from the last half of August:

–We spotted two small Columbia spotted frogs near lower Dredge Creek; they are known to breed in this area and at the community gardens.

–As I drove Out The Road one day, I noticed severe alder defoliation over long stretches of roadside. The woolly alder sawflies, assisted by the green alder sawflies, have been busy skeletonizing the leaves.

–I recently learned a new plant—a non-native perennial that appears in spots around here. I noticed it in a big clump at the beginning of the Horse Tram trail near the Eagle Valley Center. I was pretty sure it wasn’t a native, so I took a specimen to the Arboretum for the expert horticulturalist to identify. It’s comfrey (Symphytum officinale), known to gardeners as an exotic,noxious weed that spreads itself by thick underground stems(and presumably by seeds, but I found no information about seed dispersal). The pink flowers are pollinated by nectar-gathering bees, which are said to shake loose the pollen by vibrating their bodies when they are inside the flowers, but some bees can be nectar robbers and not pollinators. It is reported to be poisonous, but it also has medicinal uses.

–Along the dike trail, on the lower section before the gazebo, we noticed large stands of another invasive, exotic plant: hemp nettle, native to Eurasia. There are several species in the genus (Galeopsis). The small pink flowers are said to be bee-pollinated, but the species in our area may self-pollinate. This annual plant earns its nettlesome name by the fact that it is spiky all over (almost). The stem bears small sharp spines, the leaves are a bit bristly, and the narrow calyx that cups the base of the flower has major spines, several millimeters long. Woe betideany critter that bites or grabs this plant.

The seeds have no special device for dispersal and probably just fall to the ground, but they don’t remain viable for more than three years. A flower can make severaI seeds, which lie in the base of the cup formed by the calyx. Each plump seed is almostthree millimeters long. I was fascinated to learn that, in Europe, the seeds of an unnamed species of Galeopsis are harvested and cached by Willow Tits and used for winter food. I wonder how they do that (assuming that the birds harvest the seeds directly from the plant and not from the ground). For the species we have here (G. tetrahit), the narrow calyx cup is six or seven millimeters deep, rimmed with five sharp spines about four millimeters long. If the hemp nettle species harvested by willow tits is similar, wouldn’t the birds get stabbed in the face? And I also wonder if our chickadees will learn to do this!

–Another local naturalist observed some juvenile ravens at Eagle Beach. One of them carried a spruce cone, laid it down, and deftly extracted the seeds, one after another. Where did it get the idea—maybe from watching some other critter? Had it done this before? In any case, this seems like unusual and interesting behavior.

Thanks to Elizabeth Graham, FSL-USFS, for info on alder sawflies, Ginger Hudson at the Arboretum for identifying comfrey and showing me the hefty rhizomes, and Bob Armstrong for the raven observation.

Diverse musings

on oystercatchers, pinesap, and spittlebugs

At the mouth of Cowee Creek, sometime in mid-June, we’d found a vigilant pair of black oystercatchers, presumably with a nest nearby. A couple of weeks later, a small group of hikers stopped at the same spot and quickly noted that the adult oystercatchers were tending two tiny, downy chicks. The chicks had hatched quite recently; their legs and especially their bills were still very short (it would be impossible to fit an adult-size bill inside an egg). One adult guarded them closely while the other made short forays down the beach for food.

Oystercatcher chick. Photo by Bob Armstrong

Black oystercatchers are beach-nesters; both male and female construct the nest, which is usually made of rock and shell fragments. There may be one to three eggs per clutch, incubated for about four weeks by both parents. Eggs are reported to be tolerant of flooding by high tides. The chicks can walk and swim well three days after hatching; after about five days, they start to peck at possible food items. Very young chicks are fed mostly by the male, while the female broods or guards them. Later, when chicks can follow adults to feeding sites, the female takes a more active role in feeding them. Young ones may begin to forage for themselves at about ten days, but they are just learning, taking fewer and poorer items than the adults. They gain weight quickly, but elongation of legs and bills takes longer. Even at seven weeks, chicks get much of their food from the parents, mostly marine molluscs, the large ones cut up into conveniently small pieces. They can fly, then, but in general they are not fully skilled at foraging until they are about three years old. Human disturbance can lead to prolonged incubation and fledgling times.

The trail down to Cowee Meadow provided a nice surprise—a small, yellowish-pink, peculiar-looking plant with no green color at all. This plant is called pinesap, and we don’t see it very often. Without green pigments, it is not capable of photosynthesis and making its own nutrition. It is indirectly parasitic, tapping into the mutualistic mycorrhizal fungi that connect many green plants and carry nutrients from one to another. Connections to those nutrient-transporting fungi turn out to be essential for growth and flowering, and even seed germination of pinesap. The plant is subterranean except for the inflorescence, which pushes its way up above ground. The flowers contain nectar, and bumblebees are thought to be the main pollinators (although there may be some self-pollination too). At first, the flowers are pendant, but they tilt upward when the seed capsule is mature, thus facilitating seed dispersal.

By the end of June, the herbaceous vegetation in many meadows was decorated with the foam ‘houses’ of spittlebugs. Adult spittlebugs (a.k.a. froghoppers) can fly as well as hop, and they forage by sucking sap from the fluid-conducting tissues of plants. Stealing sap from plants can reduce the health and reproductive output of the plant, so gardeners and farmers don’t like spittlebugs. The bugs are also known to transmit certain diseases from plant to plant.

There are many species of spittlebug; the best-studied species lays eggs in plant tissues in late summer and fall; the overwintering eggs hatch in spring. The larvae (called nymphs) are sap-suckers too. They disperse from the hatching site, and once they get to a good feeding spot, they tend to stay put, molting several times as they grow inside that foam ‘house’. They produce the foam by mixing air and excess fluid from the gut with secretions (from the end of the abdomen) that stabilize the bubbles. The foam helps protect them from predators and parasites, perhaps various micro-organisms, temperature extremes, and desiccation. Sometimes several nymphs share a foam ‘house’.

Sap is not very nutritious, but spittlebugs (and many other sap-feeding insects) have help: inside certain abdominal cells are very specialized symbiotic bacteria that provide amino acids and vitamins that are used by the host insect for growth and maintenance. These helpful bacteria are apparently passed from mothers to offspring.