Trailside observations and mysteries

bear scats, baby porcupines, adventitious roots, and more

–One day in mid-August, I wandered along the Eagle River trail, just to where the old Yankee Basin trail branches off up the hill. In that little walk—only about a mile, I found twenty-four things of special interest; twenty-three of them were relatively recent bear scats. Of course, I had to check them all out. I learned that, despite the numerous chum salmon carcasses and body parts scattered along the riverbank and the live salmon still thrashing about in the river, the bears had been having a varied diet. Vegetation fibers were a common ingredient, along with some blueberry, devil’s club, and salmonberry. Several scats also contained high-bush cranberries, both seeds and whole, ripe fruits (they are ripening early again this year). Gut passage of whole fruits may not be surprising, given the short length of bear guts, but high-bush cranberries seem to pass through whole more often than other fruits—begging the question “Why?”

The twenty-fourth observation was a brownish lump beside the trail, one that moved slightly. When I stopped, the lump became a very young porcupine, busily chowing down on a small plant called enchanter’s nightshade. After watching for a while, I crept by and went on. When I returned, the little fellow was still there, still eating. This time, as I approached, it shuffled off about a foot or two, but came back immediately to the same patch and went on stuffing leaves into its mouth. There were other patches of this common understory plant nearby, only a few feet away, but something made this patch particularly desirable. Was there some other small plant in the mix in that special spot, one that added to the allure?

–A stroll with a friend along a beach yielded, among other things, a king crab shell, covered with the characteristic large, robust spines. We wondered about the function of those spikes and guessed that they probably helped defend king crabs from predators. But which predators might be deterred and how do successful predators evade or tolerate the spikes? Apparently, little study has addressed such questions.

–A little walk on one of the North Douglas trails discovered some red alder trees with many odd pinkish/orange sprouts coming out of the lower three feet of trunk. These short sprouts were quite stiff, with rounded tips. One trunk had dozens of them. What could they be? Some digging into the scientific literature via the internet and some consultation with another scientist led to the conjecture that these are adventitious root sprouts, but not the conventional type that grow out into soil just above the normal roots of some kinds of trees, in response to flooding. Adventitious root and shoot sprouts (including those that make short leafy shoots on red alder trunks) both grow from meristem tissues (localized growth centers where new cells are formed) that are part of the normal development of the tree trunk but they often stay dormant and don’t break forth from the bark. Red alders have thin bark, which might increase the sensitivity of these growth centers to environmental stimuli, such as light (for leafy shoots) or water (for roots. Similar spiky root sprouts are reported to develop on certain willows too.

adventitious-roots-s-stanway
Photo by S. P. Stanway

A return visit to these same alder trees about two weeks later showed us that most of the pinkish shoots had disappeared. The few remaining ones looked shriveled, woody, and dark. None of them had grown larger than the original two or three inches, so none of them ever became rooted in the ground.

Many questions await answers! Could these odd root sprouts be aerial roots? When sodden soils reduce the amount of oxygen that can reach buried roots, these short shoots might help supply the real roots with oxygen, which is needed for cell respiration and metabolism; they may also help eliminate carbon dioxide, which is one by-product of cell respiration. Why did only a few red alders trees make them, while neighboring alders did not? Are these particular trees growing in a site that has too little oxygen available in the soil (for instance, from saturation with water)? Although the site was damp, it did not seem damper than adjacent places in which neighoboring alders grew without the adventitious roots. Do those particular trees have roots that are damaged in some way, so they have unusual requirements that can be filled by the strange shoots? Or are these particular trees just genetically disposed to be sensitive to certain environmental stimuli such as rain-water streaming down the trunk that might have stimulated the adventitious root sprouts, perhaps on particular, very sensitive, individual trees.

–Parks and Rec hikers went up to Cropley Lake one nice day. From the treetops around the open meadows came the clear songs of olive-sided flycatchers: Quick, three beers! Quick, three beers! I often hear them here in the spring, but why would they be singing in late summer when they are about to head south on migration?

–On one of the hottest days of the year, when temperatures reached eighty degrees or more, Parks and Rec headed up the Granite Basin trail. Along the trail we found a couple of small stands of the yellow-flowered fireweed, not a common wildflower around here and therefore an unusual pleasure.

A bigger treat was the discovery that a State Parks crew had completed renovations of one section of the trail, making the way smoother and safer. And there were signs that more work is intended—bags of gravel for the muddy areas and stacked boards to replace the worn-out ones. Because this is a favorite trail for many of us, we cheered the State Parks crews.

Thanks to Robin Mulvey (Forestry Sciences Lab) and Ginny Eckert (UAF) for helpful consultation.

Out and about in mid-June

spring songs, subalpine sightings, and a choosy bear

I went, with a friend, into Sheep Creek Valley one morning, to listen to bird songs. I especially wanted to hear Swainson’s thrush, whose vigorous, upward-spiraling song is beautiful, and Sheep Creek Valley is usually a good place to hear them. We entered the valley around eight o’clock, and I heard fox sparrows, an orange-crowned warbler, a Lincoln’s sparrow, a ruby-crowned kinglet… and a few unenthusiastic, feeble-sounding Swainson’s thrushes. The valley was far quieter than I had expected, even though we missed the dawn chorus, which would have started about two-thirty—this being near the summer solstice. Then, about ten o’clock, the Swainson’s got warmed up and tuned up and sounded like their normal selves.

There’s a conifer grove in the midst of the cottonwoods, alders, and willows, and there we saw a chestnut-backed chickadee, perched just over our heads. It took a surprising interest in my cap, approaching it from front, side, and back and looking closely at it. I have no idea why it was seemingly so fascinated. The cap is red, but that doesn’t seem to signify. On the front is a picture of a crowned crane, which has a big white cheek patch (like a chickadee) framed by black (like a chickadee), and we wondered if that could have been the attraction. We’ll never know!

On another day, we wandered up to Cropley Lake, to check on the stands of yellow-flowered fireweed that grow in wet patches on the back side of the lake. We fund a big boulder to sit on while we had our morning tea and crumpets, but as we started to settle down, we flushed a female sooty grouse and a tiny chick from the dense ground cover. Mama grouse clucked and fussed, and they both took refuge at the edge of a willow thicket fringed with dense ferns. Mama kept peeking out to check on the ‘monsters’ that had entered her domain. We thought she might be waiting for a few more chicks to catch up with her, from farther up the hill, and we were perhaps keeping the family from re-uniting. So we gathered up the tea party and moved about a hundred yards away, where we may have bothered some jays. We found the yellow fireweed plants, just budding and not yet showy.

Other treats on this walk included a set of very tiny deer fawn tracks in the mud, and an olive-sided flycatcher singing from the tops of mountain hemlocks: “Quick, three beers !!!” again and again. The little insectivorous plant called butterwort or sometimes bog violet (it is not a violet, but the flower is superficially similar) was blooming, sometimes hidden in the other vegetation but often making a nice purple show in barer patches along the way.

The Dredge Lake area is once again a site for nesting American redstarts, not a common bird around here. Females do the nest-building and incubation, but both parents feed the chicks. Northern waterthrushes have been heard frequently and might possibly nest here, near some of the ponds. In addition to the usual mallards, ring-necked ducks (neck rings seldom visible) have been seen and may nest here, so we might yet see a brood or two of ducklings. The little ones don’t learn to dive well until they are about a week old, but eventually get most of their food by diving. I have reports of curious doings by tree swallows at a nest site, where more swallows than just the nest owners were interacting, and sightings of solitary sandpipers, which have the unusual habit of nesting—not on the ground, like other sandpipers, but in abandoned nests of birds such as robins.

Back home: on several days, I was entertained by the view out my front window. A juvenile bear came into the yard, which is a riot of fireweed, nagoons, horsetail, and buttercups. He (yes, definitely a male) foraged avidly on horsetail, avoiding the buttercups and spitting them out if he happened to grab one while gobbling horsetail. Very selective feeding, and probably a good thing, because buttercups are known to be poisonous to livestock and can cause contact dermatitis to humans who handle the plants a lot.