The many uses of urine

courtship and defense, signposts and bragging rights… and a few human uses too

Reading about porcupine courtship made me think about how other animals use this metabolic waste product. Urine is an excellent vector for delivering scents and hormones that are signals involved with courtship (as in porcupines) and territorial defense. Many mammals, as well as some fishes and invertebrates, makes use of this convenient and readily available delivery system for olfactory communication.

We are all familiar with domestic dogs lifting a leg to urinate on a tree or fencepost. Such scent marks are sniffed by other dogs, who can learn the identity of the mark maker from the unique mix of scents, and often leave their own marks atop the original one. We sorry humans, with our relatively poor sense of smell, sometimes have a hard time imagining the scented world of dogs and many other animals, but these other beasts can identify individuals, as well as sexual and social status, from scent marks.

Both members of the dominant pair in a pack of wolves use urine to scent-mark the borders of their territory; newly formed pairs superimpose urine-borne scent marks on each other’s previous marks, probably as a part of courtship. Territorial borders marked with urine deposits are a regular feature of behavior in a variety of mammals, including coyotes and tigers. Beaver families make small, black piles of debris marked with urine and anal gland secretions to establish claims to particular waterways; other beavers are thus given notice that the place is occupied.

Males of many ungulates (such as moose, bison) either urinate over their own legs or wallow in urine-soaked dirt as a way of chemically signaling their status. Stallions urinate on established dung piles to advertise their dominant status. Male elephants and giraffes actually taste a few drops of female urine to detect hormones that signal readiness (or not) to mate. Female crayfish and swordfish send out a chemical signal via urine to attract willing males. Urine is used for certain forms of chemical communication among individuals of some species of primates (the taxonomic group to which humans belong).

Human campers sometimes urinate all around a camp site in hopes of deterring unwelcome four-footed visitors (although I don’t think the efficacy of this boundary marking has been fully determined), but human uses of urine go way beyond simple boundary marks. In the course of history, urine has been used in several inventive ways. Perhaps best known are the roles of urine in tanning hides and as a mordant to bind dyes to cloth. In sixteenth century England, whole casks of urine were shipped across the country for use in the dye industry.

The ammonia in urine can cut dirt and grease, and so it has been used as a cleaner. Even after soap became available, urine from chamber pots was used as a household stain-remover. In ancient Rome, urine collected from public urinals was hauled to laundries, diluted with water, and poured over dirty clothes in a tub; a person then stood in the tub and stomped on the wet pile to thoroughly mix the cleaner with the dirty clothes. Commercial persons who made a business of collecting and selling vats of urine were even subject to Roman taxes.

A traditional Scottish way to treat woven wool was to soak a length of the cloth in household urine to clean it and set the dye, and then pound it on a board. The process is called ‘waulking’ and still continues in the Hebrides (and in Nova Scotia by descendants of Scottish emigrants) as a cultural celebration.

Urine has been used as a tooth-whitener and for making gun-powder. Hormones extracted from pregnant mare’s urine are one way of treating fertility and menopausal problems. More recently, stem cells extracted from urine have been re-programmed to grow new nerves and other tissues. Many other medical applications are part of folklore, and indeed may be efficacious, but they could use verification by scientific study.

Very versatile stuff!

On the Lemon Creek Trail

porcupine sign, hemlock observations, and singing birds

For weeks I’d been wanting to explore the Lemon Creek Trail, in hopes of enticing Parks and Rec hikers to go there again, after a hiatus of several years. I know the first part of the trail well—up over the saddle behind Home Depot, from many excursions to a dipper nest site that’s approachable from upstream (after a short bushwhack from trail to creek). But just over the saddle is a small swampy area and another small creek, and the continuation of the trail on the far side of the swamp eluded me.

So, one day in late March, I headed up the Lemon Creek trail with two friends, one with two feet and one with four feet. The trail was pretty icy, and we met a guy who had turned back, but our ice cleats proved themselves once more. Near the swamp, we crossed the little creek on a snow bridge, but –of course—missed the spot where the trail resumed.

So we floundered on down to some alder thickets close to Lemon Creek where the snow was still pretty deep. Soon we noticed a series of elderberry stems that had been nipped off. Sometimes the nipped-off stem was still there, and then we saw that the leaf buds had been nibbled away. Aha! So that’s what the porcupines were after. Cut off the whole stem to get a few bits of budding leaf. Most of the elderberry bushes in this area had been pruned by foraging porcupines. I have to wonder why they like the stuff—it smells bad (to me). I think elderberry has defensive chemicals intended to deter munchers, but porcupines seem to be able to deal with them, or else they are desperately hungry.

After plunging through the snow for a little while longer, I said that I had a faint memory that the trail should be a bit up the slope in the conifers. So we peered up the steep hillside, well decorated with devils club and, indeed, it looked like a trail up there. Up we scrambled, and there it was. Now I knew we could follow it back and find where it connected to the little swamp. It was a decent day, with just a little misty rain from time to time, so, having regained the trail, we went on. And the rest was ‘cake’. The trail is clear and easy to follow, probably because the research teams that go up to the glacier have kept it open.

Along the way, we commented that porcupines seldom seem to completely girdle the hemlock trees from which they eat bark; usually they just sample a patch on one side. No sooner had we said this than we came upon a twenty-foot hemlock that was completely de-barked all the way around from about one foot high to about fifteen feet above the ground. What made that little hemlock so tasty, apparently? It was outcompeted (for light) by its much taller neighbors, so maybe it didn’t have a lot of energy to allocate to defensive chemicals.

We trudged and slid along, eventually dropping back down to a broad sand flat with lots of alders and the remnants of an old log bridge. Just upstream from here, the creek makes a ninety-degree turn, and so does the trail, which goes on up the valley.

Several years ago, Parks and Rec used to be able to walk up the road through the gravel pit on the opposite side of Lemon Creek, cross a bridge, and thus get to the wooded valley that comes down from the glacier. But nowadays, one gets to this point by almost two miles of trail from the trailhead behind Home Depot. After numerous side excursions to look at things, by the time we reached the sharp angle in the stream, it was time to turn around. So we perched on a log to share a snack while gazing at the creek and wistfully contemplating another day when that upper valley could be explored.

Our return trip was uneventful, although the snow bridge that held both of us on the outward-bound trip only held one of us on the way back. But at least I didn’t get my feet wet in the little creek!

The conifers were full of talkative pine siskins and a few crossbills. Juncos flirted around in the brush by the big sand flat. Varied thrushes sang all day. Kingfishers rattled up and down the stream, no doubt checking out cutbanks in which to dig a nest hole. A dipper put on a concert down in the creek. Best of all, we heard our first winter wrens trilling enthusiastically. But technically, we can’t call them winter wrens any more. The taxonomists have decided that the western winter wrens are genetically distinct from winter wrens in the east (and Europe, where they are called The Wren). Although the plumage differences are subtle, and the songs are not very different, the calls are reported to be distinctive. So now our wrens are known as Pacific wrens.

All in all, a good day. Mission accomplished, most pleasantly. Now to see if Parks and Rec will try this trail, come summer.

Winter wanderings

ptarmigan tracks, porcupine trails, a busy hare and a winter-kill

There aren’t many activities I enjoy more than simply prowling around the forest and meadows, looking for signs of animal action. Sometimes I go solo; when I’m lucky, I have a companion or two. All this recent sunshine has enticed me out several times; it’s a shame to waste a day of sun in Juneau by staying indoors! So here are some observations (and questions) from some little explorations in the last few weeks.

–Cropley Lake: a ptarmigan had landed, sinking down a few inches in the soft snow. But for some reason, it took flight immediately, leaving a few running foot prints and two sets of wing prints, the second one very faint.

–Mendenhall Lake: ptarmigan often come down from the alpine zone in winter and forage in the shrubby flats near the lake. Sometimes I’m lucky and actually see the birds, but this time I only found a trackway where the ptarmigan had run, with long strides, from one thicket to another. There it had nibbled on willow buds, leaving barren stems.

–Crow Point near the Boy Scout camp: a porcupine had trekked all the way across the wide meadow where the geese commonly graze, from the hillside out to the spruce groves above the beach. In one of the groves we noted a cluster of young spruces with dead tops. Closer inspection revealed that the tops of the trunks and some of the upper branches had been de-barked. But this had not happened all at once: some gnawings were recent and the twigs were not long dead, but others were gray from long exposure. Thus, it seemed that porcupines had foraged here repeatedly, and I have to wonder what made that particular cluster of trees so attractive.

The beach itself was covered with bird tracks: gulls, crows, and something smaller, whose tracks were very indistinct. I was interested to note that a vole or mouse had ventured well out onto the sand; what was it after?

–Low elevation muskegs off the Dan Moller Trail: This little exploration was quite productive. We found a place where a hare had run back and forth, stopping long enough to eliminate (colorful!) waste products and nibble the buds from the tip of a spruce branchlet that had been cut from a low-hanging branch several feet away. A perambulating deer had cropped the very tips of some blueberry bushes, taking just the tenderest bits and buds.

hare-ate-spruce-buds-KMH-(2)
That red isn’t blood… it’s hare urine! Photo by Katherine Hocker

The snow was so deep that most small mammals could just burrow around under the white blanket, safe from aerial predators at least. The only small mammal tracks we saw were in the bottom of a tiny gully where the snow was thin. The mouse had run across the ice in one direction, but then walked back.

A surprising find was a dead Steller’s jay, lying toes-up under a tree. It was emaciated, with no fat deposits, so the keel on the breastbone was very prominent. Later examination revealed a digestive tract empty of all but little stones. With all the bird feeders in most human neighborhoods, it seemed strange that this bird would starve.

Porcupines

they sing and fight… and have dramatic sex lives

A young porcupine trundled up the trail ahead of us, one day in late September, before seeking cover in the forest nearby. The young ones are about half grown now and independent of their mothers. The mothers have other things on their minds, because fall is the mating season.

At this time of year, the males travel widely in search of willing females. The males ‘sing’, with a high, whining sound. Females coming into estrus send out scent signals and call with high-pitched screams or howls (as described by one researcher). One or two of these amorous creatures outside your bedroom window at night can be a little unsettling!

When a male finds a female before she is really receptive, he guards her from the approaches of other males, often perching in a tree below where she sits. Fights between males sometimes become fierce (and noisy), and the competitors end up with snouts full of quills. The battles may go on for several days. The winner then approaches the female and courts her; it may take a day or more to win her over. His first advances are often rejected with squawks and swats. He sprays her with urine from time to time; the urine presumably contains stimulating hormones. Gradually, they begin to talk softly to each other and they may rub noses. The final stage of courtship includes the male hosing her with forceful jets of urine that drench her with scent. To do this, he stands, grunting, on his hind legs and tail, with his male parts at the ready, and lets fly. This process often begins in the tree where the female was waiting, but then the pair goes down to the ground to copulate.

Copulation is tricky for prickly animals, but porcupines have it figured out. The female flattens out her quills, arches up, and brings her tail up over her back. The underside of her tail is less spiny than the top side. Copulation is brief and may be repeated until the male is worn out. One of the pair may then go back up the tree and scream, ending the encounter. The male, when he recovers, may go on to court other females. If fertilization is not successful, the female comes into estrus and may go through it all again.

baby-porcupine-and-mom-Jos
Nursing baby. Photo by Jos Bakker

If fertilization is successful, she will be pregnant, with a single fetus, for about seven months—a very long gestation time for an animal that usually weighs less than about twenty pounds. The young ones are born in spring, emerging fully equipped with quills, which dry and harden in a few hours; the babies are quite capable of defending themselves by thrashing the tail. They can’t climb until they are several weeks old but stay near the tree where the mother is foraging or napping. They start eating green vegetation when they are about two weeks old but continue nursing until they are four or five months old. Nursing is accompanied by mutual humming and purring. Apparently, the female cleans urine and feces from her baby until it is able to climb and get itself away from ground-level predators; the cleaning reduces the scent cues for would-be predators.

As the fall mating season approaches, mother and young separate. Young females tend to disperse more widely than males, before settling on their own home ranges. Females are sexually mature when one year old, but males don’t mature until age two years.

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!

First snows

some tracking discoveries and other observations

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

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

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

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

mouse-tracks-kmh
Photo by Katherine Hocker

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

 

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

 

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

 

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

 

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

 

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

To John Muir Cabin

late flowers and early arrivals

By sheer luck, a late October ramble on the Auke Nu trail to the John Muir cabin found us in partial sunshine. Some of the boardwalk was even rather dry, although most of it was still very wet and slippery. All the usual mudholes were still there, of course, and we can only hope that someday they will be filled with gravel. A major erosion channel is developing along the trail near the trailhead and a large spruce has tipped up its roots, exposing its very shallow root system.

A few dwarf dogwood and bog laurel flowers stubbornly persisted, but they waited in vain for a passing bee or fly to do the pollinating. Blueberries still hung on the bushes—we just don’t get enough migrating thrushes and wandering bears or other critters to clean out the berry crops and accomplish all the potential dispersal of seeds, especially in a year of bumper berry crops like this one.

The John Muir cabin has been nicely renovated. New floor, new table, new bunks upstairs and down, and a nifty spiral staircase to the loft. A door at the top of the stairs helps control heat distribution, and an escape hatch, with ladder, provides an emergency exit from the loft. New windows offer great vistas and ventilation if needed. There are lots of pegs for wet rain gear and grab bars for swinging into the upper bunk.

The wood stove now sits in the middle of the floor, with space around it for folks to move about. The propane heater works well. And there’s a brand new outhouse, complete with gravel walkway from the cabin. Pretty cushy!

October is the mating season for porcupines. The babies of last spring are still very small, but they are now on their own, chowing down on the remaining herbage before shifting to a winter diet of bark. So their mothers are ready to mate again. If you hear strange calls coming from up in the tree canopy, and you are pretty sure it’s not an unusually inventive raven, it might be a male porcupine announcing his availability to nearby females or perhaps a couple of males squabbling over mating privileges.

Winter arrivals from the Interior have been here since September. Slate-colored juncos now mix with our local Oregon juncos at feeders. Black-billed magpies call raucously, visit seed feeders, and are constantly on the lookout for something better. They are good scavengers, and salmon carcasses are high on the list of favorites. Just recently, I saw an eagle perched on a rock in the Mendenhall River with a dead coho at its feet. Hanging around, just out of the eagle’s reach, was a hopeful magpie, waiting to dart in for a morsel or two. No doubt there were a few more magpies lurking nearby.

Postscript on the Bear Creek Dam in Douglas:

Some weeks ago, I wrote about the early history of this dam. Here are some tidbits about later history there. The CBJ water department tells me the dam was decommissioned in 1985, when Douglas went onto the city water system. No one currently at the water department knew about early maintenance activities at the dam, but some Douglas residents remember that CBJ occasionally cleaned the walls of the reservoir when water was low. At low water, residents could hike up the canyon above the concrete dam and find an old log dam, presumably left from the abortive attempts to mine that area. When the reservoir was full, this was a popular spot for picnics and swimming in summer, and for skating in winter. Between the dam and 5th Street is an old viewing platform, reportedly sponsored by Gastineau School for access to the creek and class projects.

The dam is reported to be structurally sound still, and the CBJ water department goes up there once a month to make sure the tailrace is clear of obstruction, so water flows freely through the bottom of the dam.

An early autumn

Leaves and flowers, fish, mammals, and birds in transition

Fall came to Juneau in mid August. Cottonwood trees began dropping yellow leaves and alder leaves browned and shriveled. The air felt different, and it smelled different, too. On fine, sunny days, clouds of fireweed seeds, floating on their white parachutes, filled the air and collected in windrows on the shores. Mushrooms appeared all over the forest, as if from nowhere.

The grasses and sedges in the coastal meadows slowly changed from green to yellow and gold. Although the splendid pink flowers of fireweed were gone, the stems, leaves, and pods still filled fields with pink and red.

At mid elevations, a few fireweed stalks still bore flowers and some had, in fact, just started to bloom. But the deer cabbage leaves already showed yellow and orange and russet. As the rains increased, the once-fluffy heads of cottongrass drooped dismally, like small mop-heads. But there seems to be a bumper crop of highbush cranberries, glowing brilliant, translucent red (slightly less ‘bumper’ now, after my visit…).

Flocks of robins scoured the roadsides for grubs and worms. In Sheep Creek valley, robins, varied thrushes, and whole families of fox sparrows foraged on elderberries. Near Steep Creek, dozens of warblers flitted from bush to bush. Most were yellow-rumped warblers in immature plumage, but the flocks included several ruby-crowned kinglets and occasional Townsend’s warblers and orange-crowned warblers. I was interested to observe the reactions of the crowds of visitors who waited, mostly impatiently, for a bear to appear. Almost none appeared to notice the many warblers that flew back and forth across the creek and gleaned bugs from the shrubs.

If the bears were occupied elsewhere, many folks enjoyed watching porcupines—studies in slow motion. There were several small ones (known as porcupettes), born last spring, that frequented the Steep Creek area. They were now largely independent of their mothers, foraging on their own and growing perceptibly from week to week. Sometimes one would spend several days in a single cottonwood, taking long naps in between sessions of shredding and skeletonized the leaves. We watched one chomping on willow leaves for a while and then wandering to the creekside, where it avidly consumed dwarf fireweed and then drank from the creek.

The sockeye run in Steep Creek dwindled dramatically during the last two weeks of August. The few remaining pairs of salmon were attended by lots of Dolly Varden, which eagerly line up behind a spawning pair. Dollies, young coho, and sculpin all love to gobble up loose salmon eggs.

Foraging bears left partly eaten salmon carcasses on the streambanks, and it wasn’t long before the flies found them. Soon some carcasses were squirming with hundreds, maybe thousands, of fly larvae (maggots). I was initially surprised to see a bear lick up a pile of maggots and then show one of her cubs the tasty little morsels remaining from her snack. On second thought, however, there should have been no surprise, because bears eat grubs and ants and bee larva when they can. But this was the first time I observed bears eating maggots instead of salmon.

A family of well-grown mallards, still accompanied by mama, foraged regularly in the creek. They scarfed up unburied salmon eggs, enjoyed a snack of maggots on old carcasses, and enthusiastically ate fresh salmon meat when a bear abandoned its catch.