Trailside observations

In sun and snow and sleet and hail…

Here’s an assortment of winter observations that gave pleasure to some trail-walkers.

–Late November, Eaglecrest. Parks and Rec hikers on snowshoes went up the road, but the majority decided to go home for lunch. Two of us went on, over toward Hilda meadows, and perched on a log for a snack. Too busy feeding our faces for a few minutes, we eventually began to notice what was around us. Right behind our comfortable log was a big spruce tree with two lumps at the very top. The upper lump was pretending to be a moss wad, while the lower one was eating spruce needles. Both young porcupines were very wet, but the lower one suddenly roused up and rapidly shook itself dry—moving faster than I’d ever seen a porcupine move. The upper one slept on.

–Late November, Mendenhall Lake beach. A small stream flowed over the beach, creating a little opening in the ice. Three eagles were bickering over the remnants of a salmon carcass, which was probably fairly fresh (judging from the bright red blood stains on the ice). We often see late-spawning coho in the streams that feed the upper Mendenhall (years ago, in December, I counted over a hundred eagles on the stretch of Dredge Creek below Thunder Mountain; they were there because the creek was full of coho). One of the eagles snatched up the tail piece and flew off, hotly pursued by a pirate that eventually won the tasty morsel.

–Mid December, Eaglecrest. Lovely soft snow covered the ground, so animal-tracking was really good. Shrews had been very busy, running over the snow from one bush to another. Lots of other mammals had been active, too: deer, weasel, hare, porcupine, red squirrel, and mouse. Sadly, we found no ptarmigan tracks at all.

–Mid December, Dredge Lakes area. After a deep freeze, a warm spell had melted ice cover and opened up some of the ponds, and beavers had become active. There were new cuttings in the woods, new twigs in the winter caches, and some of the perpetrators were repairing their dams. The Beaver Patrol was called out of its own winter torpor to make notches in a few dams, lowering water levels in certain ponds so that nearby trails were dry , permitting passage of any late-spawning coho, and allowing juvenile salmon to move up and down stream if they chose to do so.

beaver-in-winter-3-Kerry
Photo by Kerry Howard

–Late December, Mendenhall wetlands. ‘Twas a very uneventful walk in a blustery wind. But suddenly two small birds blew (not flew!) in and tumbled into the grass. Righting themselves, they revealed themselves as a pair of gray-crowned rosyfinches, a species I’ve seen in upper Glacier Bay and on Mt Roberts, but not out here. That turned the day into a ‘plus’.

–Late December, Dredge Lakes area. Very low temperatures had refrozen almost all the ponds and streams. However, the ditch from Moraine Lake to Crystal Lake had a couple of very small ice-free patches. And there we saw a dipper, bobbing in and out of those dark pools, no doubt very hungry.

Any sensible dipper would go downstream, perhaps to an estuary, where bugs and fish would be more available!

–Early January, Herbert River trail. A mink had coursed along the elevated riverbank, in and out of the brush, occasionally down to the water’s edge. A set of extremely large moose tracks crossed the trail. That long-striding giant was really moving—the foot prints were often five feet apart. The trackway led through brush and over the arching branches of a fallen tree—almost four feet above the ground. Those long legs! I would have loved to watch that beast (from a respectful distance)!

–Early January, Perseverance trail. Recent heavy rains had brought down some small landslides, not unexpectedly. Unlike the trails near the glacier, this one was nearly clear of ice, and walking was easy. There was fresh snow on the ground, up past Ebner Falls, showing up a few porcupine tracks and some very recent red squirrel trackways. A mouse had crossed the trail with big jumps, several times its body length, leaving clear footprints as it hustled into cover across the open trail. I like seeing mouse tracks, in part because I don’t see them very often.

–Mid January, Switzer Creek area. Before the predicted rains and rising temperatures wrecked the lovely fresh snow, we found tracks of deer, porcupine, possible coyote, and a few mysteries. A shrew had scuttled across the soft snow, making a narrow groove marked by its tiny feet. A good find was a trackway of a grouse, striding through the snow and under low-hanging bushes in the woods. This took a few minutes of searching to determine the track-maker, because the new snow was so soft that it often fell down into the tracks, obscuring the prints. But finally we found good marks of three avian toes.

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Mid-April

early flowers and musings about ducks

Skunk cabbages stand as tall yellow sentinels (if deer haven’t nipped them off) in the marshy places. They send out their sweet aroma (not at all ‘skunky’!) and provide a cheery splash of color in the mostly gray-and-green forest. Yellow violets gleam along the forest trails, as the forest floor begins to green-up. The white flowers of miners’ lettuce are showing, along with the delicate little flowers of fern-leaf goldthread. And the purple mountain saxifrage is going strong on rocky outcrops even in the shadier sites.

fern-leaf-goldthread-early-development-through-the-snow-6-good-altered
Fern-leaf goldthread flowers emerging through the snow

Blueberry bushes at low elevations have already dropped many of their little pinkish bells. The deeper pink flowers of salmonberry are borne on canes that are just sending out new leaves. In addition to the early-blooming felt-leaf willow, other kinds of willows are producing their catkins.

In many places, alders have already dropped their male catkins, which have released their pollen for the wind to carry to the waiting female cones. I’ve found lots of catkins lying on the ground under male cottonwood trees too, but for some unknown reason, a substantial number of these have released only some of their pollen. However, the best part (for me) of cottonwood flowering is the light, clear, sweet aroma that fills the air near a stand of these trees. Look on the ground below a tree and find the yellow-brown bud scales and sniff ‘em!

I heard my first fox sparrow of the year in Sheep Creek valley recently, along with the varied thrushes, robins, Pacific wrens, and ruby-crowned kinglets, which have been singing for some time. Just a few days later, there were several singing fox sparrows in the valley. Although hermit thrushes are here, I’ve not yet heard them sing. I have two reports of chickadees cleaning out their nest cavities, and on one creek I have seen a male dipper on guard as his female incubates their clutch of eggs; with such an early start on the first brood, they should be able to rear a second one as well.

Here are some other sightings that were fun:

A pair of ravens harassed an eagle as it sat in the top of a tree, diving at it and yelling. Poor old eagle just hunched its head and took the abuse. Were those cranky ravens defending a nest? It didn’t seem so: after some minutes of continual persecution, both ravens took off and disappeared in the distance.

Out at the end of the Mendenhall Peninsula, under overhanging alders above the beach, I found a number of small piles of chewed-up, very clean barnacle shells. Some consumer had routinely used this place to off-load the shelly ballast after lunching on the prey. Who was the consumer? Maybe a raven or two, or perhaps some otters?

One day we found five pairs of buffleheads on Cashew Lake in the Mendenhall Glacier Rec area. Each pair cruised sedately, male and female side by side, occasionally diving, each pair in a different part of the lake. Suddenly a big kerfuffle broke out—much flapping and splashing and squawking. One male had decided to approach another male’s female, and that was cause for battle. The intruder was chased off, but only temporarily. He was soon back again, and the uproar was repeated, several times. The female who was the object of interest seemed to float quietly at a little distance and let the males duke it out. I think the original status quo was restored, but who could be sure, without banded birds!

Buffleheads are the smallest diving duck in North America. They nest in the Interior, in boreal forest and aspen parklands, near small lakes and ponds, where they feed on aquatic insects. They nest in cavities made by large woodpeckers such as flickers, but readily use nest boxes too. If buffleheads try to use a cavity with an opening that is large, they may be outcompeted and even beaten up by goldeneyes that want the same cavity.

They are reported to pair up mainly in winter but also during northward spring migration. Courtship and sometimes even mating occur en route. Buffleheads often keep the same mate from year to year, according to researchers. The interactions we saw on Cashew Lake suggest that mate fidelity may be challenged at times. There’s more to be learned about all this!

Drama on the home pond

aerial attacks on fuzzy chicks

A great ruckus arose on my pond, one afternoon in early June, while I was leisurely scribbling, comfortable in my big easy chair: agitated high-decibel quacking of mallard. Of course, I leaped out of my chair to see what was happening, just in time to see an eagle swoop up from the pond into a spruce tree, dropping a couple of feathers as it landed.

Quickly, I checked the surface of the pond—a female mallard had been bringing her brood of ten tiny ducklings (not much bigger than my fist) to the pond to forage. There was a special place on the far side of the pond, right next to a tuft of weeds, where she would call them to come and rest under her wings. Having watched this family for a few days, of course they were ‘my’ ducks and I didn’t want them to become an eagle snack.

I immediately counted the little ones—no easy task, because they were scooting all over the pond, in and out of cover. But finally, all were accounted for. Mama mallard went on quacking, about one quack per second, for the next two hours. Upon consideration, I guessed that the eagle’s failed attempt had been on the female herself; a duckling would hardly have made one mouthful.

That eagle sat in the tree for over an hour, all of its attention clearly focused very intently on the duck family. It was not distracted by a bunch of juncos flitting about in the tree or around the seed feeder, or by me going out on the deck. A hummingbird close by its head warranted only a sidelong glance. Twice in that long span of time, the eagle thrust forward its head and started to lift its wings, as if to launch a new attack. But then it settled down again, one foot tucked up under its feathery skirts.

Meanwhile, the little ducklings often ventured out from the shelter of overhanging alders to forage. They were adept at diving and scuttled over the pond surface in all directions. Mama duck managed to call them back periodically, only to have them scoot out again. But she herself seldom went far from those protective alder branches.

After more than an hour, the eagle did some intensive preening and took off, but the female duck went on quacking, loudly and constantly. All the ducklings scattered over the pond, foraging actively, while mama continued to fuss. About thirty-five minutes later, back came the eagle and made another pass. Failed again and went to perch in the spruce tree. This time, however, it was very inattentive, fidgeting and looking all around, and it flew away after about five minutes. Needless to say, during all this activity, I got no writing done at all.

The departure of the eagle was a relief for both me and the female duck, although she went on protesting for another hour. The little ones were, naturally, oblivious of the threat, responding only to the need for food and (sometimes) the instructions of their mother.

Several days later, all the little ducklings were still accounted for. They were bigger now, maybe almost twice as big as before. Mama duck had more trouble fitting them all under her wings when they rested. In addition, on the pond was a solo female, who probably lost her eggs to a predator, but who was assiduously attended by a male that was still nattily dressed in breeding plumage. So perhaps she will have another chance to rear a brood.

This was the first time I’d ever seen an eagle at my pond, in all the twenty-five or more years of watching. There has been the occasional pygmy owl, and several goshawks. All the ‘gos’ were in brown plumage, i.e. not that of an adult male. Some of their attacks were successful. Of course, I have to wonder what predatory events I might have missed, while otherwise occupied.

Another day, another place: the day after the eagle threat, Parks and Rec hikers went to Cowee Meadows. We always go there in June (some of us go twice) to revel in the wildflower show. This is the fantastic meadow where we have, several times, recorded over seventy (!) species of flower in bloom in June. This time, we didn’t count them. Nevertheless, we enjoyed a good showing of lupine and buttercups; shooting stars were still splendid and the wild irises were just starting to open. More will come, later.

Some welcome news is that the state park crews have been working on the muddy, root-y parts of the trail, making it easier and safer for walking. They were at work on this day and we all said a big thank you. Yay, State Parks!

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!

Hunting success

… you can’t win ’em all

One day this fall I watched a juvenile great blue heron that was fishing in Steep Creek. In typical heron fashion, it stood motionless for long minutes, then quickly jabbed its long bill down into the water after some hapless little fish that passed by. When one hunting spot petered out, the bird moved over to a new perch and waited again. Altogether, it made over a dozen tries to capture a fish and succeeded about one third of the time. A success rate of about thirty-three percent is not too bad, although an adult, with more experience, would likely have done better.

Those observations got me thinking about the success of predators in general. How often are they successful in prey capture? What proportion of capture attempts is successful?

Perhaps the best-studied wild predator in North America is the wolf, so that is a good starting place. Admired for their strength and intelligence, respected for their close family life, wolves are sometimes reviled as competitors to human hunters. Just how successful are wolves, when they go hunting? I focused on wolves hunting ungulates (such as moose, deer, sheep), because that interaction has been the most studied. Wolves also eat beavers, hares, mice, and fish, of course, but there are no data available on those interactions.

Hunting success of wolves obviously varies with many factors, including prey density, wolf pack size, physical condition of the prey, snow depth, escape routes for prey, and so on. Reviewing a number of research reports, I found that, for wolves hunting moose in winter, as many as 38% of hunts might be successful, but usually fewer than 10% of hunts are successful. And captured prey is sometimes lost to scavenging ravens or bears.

It is interesting to compare those figures with those (courtesy of ADFG) for human hunters of moose. The average recorded success rate over a ten-year period for much of Southeast was less than 25% (with the notable exception of one subunit in which humans were successful 63-100% of their hunts!). To take two examples from farther north: In Kenai and Talkeetna, 10-22% of moose-hunters were successful.

It is harder the find data on the frequency of moose kills by wolves, which also varies enormously. Although wolves are capable of killing two moose in one day when hunting is easy, far more commonly there are three or four days between kills (sometimes even eleven days or more). Records for human hunters show that it often takes two to four days for a successful hunter to get a moose.

Although statistical comparisons are not feasible, the data suggest to me that human hunters often have higher success rates than wolves, when hunting moose. In addition, there are at least three salient differences between wolves and humans as predators of moose. Wolves are not constrained by regulations; in the absence of regulation, the human success rate would probably be still higher. Each human hunter generally takes only one moose per season, but of course the wolves hunt repeatedly throughout the year. Hunts by humans tend to be heavily concentrated in areas that are easy of access (around settlements, or a short boat ride from town, for example), sometimes to the point that the prey population is quite depleted in those areas. In contrast, wolf hunts are typically widely spaced, often many miles apart, as each wolf pack ranges over its large territory.

Wolves hunting deer in winter are recorded to be successful on fewer than 20% of their hunts, although occasionally they may succeed up to 50% of the time. By comparison, humans in Southeast were successful 30-71% of their hunts (in various management units), on average. For Dall sheep, wolves caught one in fewer than 33% of their hunts, and humans averaged 28-46% success. Again, the numbers suggest that humans often may be somewhat more successful than wolves.

Bald eagles are another fairly well-studied wild predator, and data are available from all over North America. There are a few reports that eagles are more successful in capturing fish than waterfowl (for instance, 90% vs 20%, respectively), but most reports do not separate the two sorts of prey or the age of the eagles. Nevertheless, when fish comprise at least 90% of prey taken, the success rates tend to be quite high, ranging from 47% to 73%. In these cases, there was no information on what species of fish were caught, and I found no data on eagles catching salmon or herring, which would be very relevant here in Southeast.

For fun: here are a few other serendipitous bits of data: Coyotes hunting snowshoe hare succeeded 28-69% of the time, compared to 20-40% for lynx hunting hare in the same area. Orcas hunting minke whales off the shores of British Columbia and Southeast Alaska were successful in four of nine observed hunts (45%); orcas hunting humpback whales in Argentina were successful 21% of the time in open water and 34% of attacks on beached whales. Great blue herons in Nova Scotia were successful in 29-100% of their strikes on fish prey.

One striking feature of such observations is that hunting success for any species varies enormously, which must have huge consequences for the predators. I did not find information on how much energy is expended on a hunt (and perhaps how much energy is spent defending the catch from competitors) compared to how much each predator gains by eating the captured prey. Some times or places might make it easy to obtain the energy needed for daily maintenance and for reproduction. But many predators must sometimes be close to starvation, and thus be faced with the hard choice of whether to hunt harder or to rest in order to conserve energy. The critical importance of getting enough food is one reason that juvenile animals commonly have a high mortality rate, before they learn to become proficient hunters. Some predators, including orcas and wolves, often use sophisticated strategies and complex tactics in capturing prey, and in such cases, the learning period for juveniles is extended to several years.

Wonderful Winterland

herons, swans, and an eagle’s dinner

I love just prowling around in the snowy woods, looking for whatever presents itself. Solo or shared, there is usually something of interest. Here are a few examples from the past two months.

In November, just after the first good freeze-up, I poked around on the Old River Channel (think Mendenhall River, maybe a hundred years ago or so).A great blue heron had paced–in vain—along the now-icy runnel below a beaver dam, where no fish could now be grabbed. Then I saw some huge prints of webbed feet, bigger than my hand. No goose or duck or gull; this could only have been a swan. Following the tracks, I came to a place on the ice where the swan, perhaps with some friends, had dithered around for a while. They too were cut off by the ice from any tasty green vegetation in the water below. As they dithered about, they left samples of previous meals on the surface of the ice.

By now, my path had been crossed by another retired biologist and well-behaved canine companion. Together we inspected the digested remains of swan dinners and concluded that the swans had nibbled on their own excreta, recycling the material and probably extracting more nutrients. Well, if you can’t reach the fresh stuff, perhaps this is a reasonable alternative! I wonder how often they do this—is it only occasional, for instance when ice blocks the access to fresh greenery?

Some of those huge webbed footprints led away from the resting and feeding site. They gradually got farther and farther apart, until the last strides were separated by at least seven feet. The very last one was matched with the brush of a single wingtip in the light snow. A seven-foot stride on shortish legs meant that bird was really hurtling itself into flight.

Although swans sometimes overwinter in Southeast, most of them migrate to slightly more southerly realms. Several swans had been seen in the upper Mendenhall River on the days before my little exploration, but increasing ice cover was making further stay a hungry proposition for them.

In midDecember, Out the Road (in Juneau that is a place, not just a direction), we noticed two eagles hunkered down on the bank of a small stream. They were intently staring at a dark, furry object in the water. We were ‘dying’ of curiosity, of course, but didn’t want to disturb the eagles. So we went on, saying we’d stop to look on the way back. When we did so, the eagles and the dark object were gone. All we could do, then, was check out the spot for any signs of what had been there. We found a beaver tail, some gobbets of flesh, and a rib. Perhaps the carcass had shifted farther under the ice at the edge of the stream, but maybe more likely, one of the eagles had appropriated the thing for itself. By midDecember, beavers are usually hanging out in their lodges, awaiting ice-out. So why this one was here, and how long it had been there, was puzzling.

Mid December also found us wandering around some of the ponds in the Mendenhall Glacier Recreation Area. Walking over the ice on the ponds gives one an entirely different perspective from one on the trails or in the thickets. A bonus is walking in actual sunshine! One pond has several beaver lodges that, in four years of monitoring, have never shown any sign of current occupancy by beavers. This time, we noticed small holes in the side of two lodges, with small footprints making a trail right into that doorway. It looked as if mink had moved in. Out in the middle of the pond there were three round holes in the ice, kept open, perhaps, by mink diving in for fish.

Just before Christmas, I ambled over another pond. By now, we had had several more nights of single-digit temperatures, and the ice was really solid. But there were two holes in the ice that had just recently frozen over. And there was a trackway, made by several animals, running from one hole to the other, and then on toward shore. Following these round-pawed tracks, I came upon a sizable hole under some tree roots, and there the tracks ended. I surmised that a family of otters had used this hole as a part-time den; in the past week or so, a group of three pups and an adult (presumably Mom) had been seen fishing in the few ice-free spots that remained.