The weasel family

carnivores of many shapes, sizes, and lifeways

Ermine in summer coat. Photo by Kerry Howard

This taxonomic family (Mustelidae) of carnivores is familiar to Juneau folks in the form of weasels, wolverines, martens, mink, and otters. Mustelids are a species-rich family, with fifty or sixty or seventy species, depending on what source you read. They originated over twenty million years ago from a wolf-like ancestor and have evolved into a variety of ecological niches. They are distributed naturally over all the continents except Australia and Antarctica.

Mustelids range in size from the tiny least weasel, weighing up to about 250 grams (8.8 oz) to the sea otter, weighing up to forty-five kilos (99 lbs) or occasionally more. A long-extinct mustelid is estimated to have achieved the size of a black bear or a jaguar, the biggest mustelid on record. Known as Megalictis, it once roamed the North American plains and probably preyed on many kinds of animals. 

Members of this family generally have rather elongate bodies,relatively short legs, and short muzzles. Most are highly carnivorous, typically pursuing rodents, fish, and other small critters, and most are solitary predators, but some are quite social. Certain members of the family occupy diverse, fairly specialized ecological niches—A few very social, some very arboreal, others fossorial (burrowing), some highly aquatic. It would be tidy and convenient if such specialized habits were associated with branches of the evolutionary tree of mustelid radiation (social species on one branch, fossorial ones on another, etc.). But that’s not generally the case—those habits have often arisen independently on the several known branches.

The long, slender body form of weasels is well-suited for these predators to pursue voles and mice into narrow tunnels and tightspaces. Similarly, that body shape enabled the North American black-footed ferret to chase prairie dogs down into their burrows. But that’s a sad story: thanks to habitat destruction and poisoning programs by uncaring agriculturalists, prairie dog colonies are few and scattered; the ferrets were declared extinct in the wild; captive-raised ferrets have been reintroduced in several places.

American badgers originated early in mustelid evolution, in a lineage distinct from other extant mustelids, and are quintessential burrowers. Much heftier than the weasels and ferrets, they have powerful forelegs with strong claws that enable them to dig deep and extensive burrow systems. Largely solitary, they are major predators of rodents and other small creatures of the prairies, but they too are far less common than they were.

American badger. Photo by Kerry Howard

The European badger is not closely related to the American badger, despite the shared name. A mighty burrower, it is quite social, living in multi-family, complex burrow systems. It’s a predator of worms, insects, hedgehogs and other small vertebrates, but also eats some tubers and roots.

Honey badgers (or ratels) of Africa and Asia evolved early in mustelid evolution and are not closely related to any other mustelids (including other “badgers”). They are typically solitary predators, fiercely chomping up all sorts of prey and raiding bee nests for honey, and they are good burrowers.

Arboreal species tend to be more omnivorous than the others, often eating lots of fruits in addition to small animals. The tayraof Central and South America is probably related to the martens of North America, but it’s somewhat bigger and longer-legged. It can cavort very capably in the treetops, using its big tail for balance. However, the only one I ever saw was on the ground; it burst from the brush beside a trail, giving me (not knowing that such things existed) quite a startling!

River otters. Photo by Kerry Howard

Aquatic living is typical of mink and the distantly related otters. These species eat chiefly fish and invertebrates such as crabs and crayfish, in some cases also eating birds’ eggs and nestlingswhen available. The sea otter is the most aquatic of all, seldom coming ashore. It’s the biggest extant mustelid, with large, webbed hind feet. Its dentition is much modified from the basic carnivore plan—the molars are broad and flattened, made not for cutting but for crushing shelled invertebrates.

Next in size is the giant otter of South America, which is not very closely related to the other otters. It is very social (unlike most but not all other otters), living and hunting in cohesive, extended family groups and defending the family territory with loud choruses. With webbed feet and a muscular tail, it is a strong swimmer. Group members hunt together: fish are the primary prey, but sometimes also taking snakes and small caiman. It is now endangered.

Winter may be here

edging into a colder season

The days grow shorter and darker, until we turn a corner at the winter solstice and the sun slowly starts to come back. At this time of year, my little excursions tend to be short too. Even so, some things of interest always appear.

Around Thanksgiving time, the West Glacier Trail offered a spectacular collection of hair-frost displays. A cold snap froze many rain-soaked sticks, forcing out thin strands of ice. Some displays featured long stretches of two-inch long curved strands; other displays had multiple sets of shorter strands, each one curling in a different direction, like an enviably wavy hairdo.

Dippers were sometimes foraging and singing in Steep Creek. Two otters, possibly a female with a juvenile, were fossicking about in a nearby pond, observable from the viewing platform. Eventually they went over a small ridge toward the pavilion—and as I went up the ramp in the same direction, I could look down into another pond, where I saw the otters again. The bigger one caught a nice coho and both otters went up the bank to feast. Later, I learned that this was a fish that had been radio-tagged by the Forest Service in the Holding Pond—a fish that apparently backed out and went farther up-river to try Steep Creek instead. The remains of this fish were found by a Forest Service fish biologist.

At the lower end of Steep Creek, a beaver dam slows the main stream just before it reaches the lake and creates a good pond for the beavers’ lodge. Unfortunately, in late November and early December, some very unhelpful person(s) were destroying part of this dam, which thus drastically lowered the water level in the pond. This vandalism served no useful purpose whatsoever. The pond protects the entrances of the beaver lodge; this is the lodge featured in the educational ‘beaver cam’ in the visitor center, allowing visitors to see beavers at home. The pond is also habitat for over-wintering juvenile salmon, as well as feeding sites for dippers and ducks. There were no more coho coming in, and in any case, they commonly enter this pond over a small dam off to the side. Fortunately, a spell of warm weather melted the ice and allowed the beavers to repair the breach in the dam to some degree—there were several new beaver trails going up the banks, for collecting more repair material.

I like to walk along the lake shores when the water level comes down. It’s often a good place to look for animal tracks and sometimes an unusual bird. In late November, I found a nice group of swans in the Old River Channel—three adults and a juvenile—in a spot that seems to be popular with swans on migration.

Then, at the very end of November, there was some snow at Eaglecrest, so it was fun to see what animals had been out and about. Two little explorations with friends noted the usual perpetrators– hare, porcupine, weasel, red squirrel, shrew, a possible coyote, and numerous tracks of deer of all sizes. By the end of the first week of December, there was a lovely thick blanket of snow, traveled by the same array of critters and, by us, on snowshoes. In addition, a small bird, probably a junco, had hopped over a still-open rivulet and spent a lot of time jumping up to reach some seed heads that poked up out of the snow.

In early December, the snow in one of the lower meadows on Douglas was too crusty for the tracks of small things. But again there were lot of deer tracks. A tiny shore pine, no more than three feet tall but possibly quite old, did not seem to be doing very well. It had only eleven tufts of needles on the few living branches. But it bore dozens of old cones—perhaps this was its last attempt to reproduce.

Over on the Outer Point Trail on north Douglas, a friend and I remarked with great pleasure that the recently revised and improved trail passes just below the long beaver dam, leaving the dam undisturbed. Major kudos to CBJ and Trail Mix for using ecological sense!

In the first muskeg after that beaver dam, I noticed something that I should have seen on one of the many times I’ve passed that way: Most of the small pines (less than about three feet tall) were thriving, but virtually all of the mid-size ones (six to ten feet tall or so) were dead. This pattern is not repeated in other muskegs that I have visited recently. So the question is What kind of event(s) might have wiped out a whole size-class of shore pines in this place?

On our way down to the beach, we spotted a few varied thrushes and a red-breasted sapsucker that should have been on its way south by now. We startled a small porcupine, who scuttled off a few feet and waited for us to pass. At the uppermost edge of the beach, a sprawling little herbaceous plant had green leaves and out-of-season buds. Two alders had crossed their branches very closely, rubbing hard against each other until each one had flattened scars where the rubbing occurred. We joked that now they are just ‘rubbing along together’ more or less comfortably.

A stroll with another friend in the Dredge Lake area was not very eventful until we were almost finished. On the trail ahead of us, we spotted two birds. It was so dark that almost no color could be discerned, so it took us a minute to decide what they were. Juncos? No, too big and they were walking not hopping. Blackbirds? No, tail is too short and bill is too stout. Then one of them hopped up into a nearby shrub and a white wing bar could be imagined. But what really gave them away was their characteristic behavior: they were snatching the fruits of high-bush cranberry, stripping and dropping bits of pulp, and gulping down the seed. Bingo! Pine grosbeaks doing their namesake behavior: their scientific name is Pinicola enucleator, meaning pine dweller that extracts ‘nuts’ or seeds.

Tracks in December

tracings of life in an unusually warm winter

A warm, very wet spell in early December made the lichens and mosses all perky and colorful. Beavers left their distinctive foot marks in a thin dusting of snow and swam out around their winter caches of twigs, tail-slapping when we passed by. In a ‘real’ winter, they would be tucked up into their lodges, snoozing a lot, talking quietly with their offspring, and occasionally nibbling a twig from the cache. The kits of the year, however, would be chewing twigs all winter long, as they continue to grow. Bears were out and about too, mom and cub leaving their tracks near Dredge Lake, instead of entering into serious hibernation. That entails a profound reduction of metabolic rate, shutting down digestive processes, and very little activity inside the den, quite a contrast with beavers.

Then, in mid-December came a lovely and welcome snowfall, just a few inches at sea level. It wouldn’t last, of course, in this time of warming climate, so I dug up my snowshoes and headed to Eaglecrest. There the snow was maybe a foot or so deep and just right for poking around on a day when the lifts weren’t running. Snow was falling thick and fast, quickly covering any little tracks of mouse or shrew. But under the trees were prints of snowshoe hares. A small-footed canine creature had run across a wide open area, leaving a long, straight line of well-spaced prints. There was no evidence of any human anywhere nearby, so I guessed that a coyote had raced along. But very few critters made themselves visible—a porcupine that seemed to think that if it could not see me, then I could not see it; and one flying insect, probably a stonefly. Nary a bird to be heard or seen not even a hopeful, attendant raven.

A couple of days later, a nice little cold snap meant that even at sea level, there remained a few inches of snow cover. I went out the road to some meadows, where I plonked along on snowshoes—a convenient way to deal with snowy humps of frozen grass. Oddly, there were no shrew tunnels to be seen, nor any squirrel tracks, and again not a bird could be found.

But otters had been quite busy. They had fossicked along a tiny rivulet, trampling some spots quite flat; there were more than one of them, apparently, so perhaps a family of mom and well-grown pups. I lost their trail when it went under the trees where there was no snow. However, a few minutes later, I encountered their characteristic slide marks where they had crossed a snowy, open area, pushing off strongly with the hind legs and gliding smoothly even over flat ground. This is probably more fun than stomping around on snowshoes! A bit farther on, otters had come up out of a tiny stream and snuffled all around the nearly buried ends of several low, trailing spruce branches. What was going on there, I wonder.

Some days later, I looked for tracks in another meadow out the road, but there had been little recent activity. A couple of squirrels had explored the meadow edges, out of the trees and back again, diving under humps of bent-over grasses. Before the last little snowfall, porcupines had trundled over the meadow in several places, on their usual meanderings. They seem to travel quite extensively, perhaps in search of just the right twig to nibble (?). Along a small creek, some critter had burrowed into the bank in several spots—possibly an otter.

Surprisingly, there were no little shrew-size grooves on the surface of the snow, no tiny holes where a shrew dove under the white blanket. Yet this was a meadow that, in previous years, had been laced with trackways of shrews. One shrew had even taken a dive off a vertical mudbank and gone skittering over a gravel bar in a creek. But where are all those shrews now?

A fluttering on the creek-bank caught my eye and eventually turned into a dipper. This bird was foraging along the water’s edge but apparently found little of interest, because it soon took off, upstream. That was the only living animal to be seen, except for one red squirrel crossing the creek on a broken-branch bridge.

Later that day, on another stream, I checked a long-occupied beaver lodge. There were no signs of recent beaver activity here, although the lodge may be currently occupied. However, other woodland folks were interested in the place: porcupines and mink had visited on more than one occasion in recent days. Was this perhaps a multi-species condo? It wouldn’t be the first time that happened.

The slanting light of midwinter that stabs one blindingly in the eye at certain times of day on Egan Drive, did some beautiful things out by the meadows. Some conifer-clad hilltops were brilliantly lit, contrasting with darker slopes below. Light mists collected in the valleys caught the light rays and turned golden. Overhead, some dark clouds gathered amid some white fluffy ones, but bright rays came through the many unclouded areas, where blue sky was a cheery sight.

Three little stories

Otters on the ice, fish at an upwelling, and an unusual feeder visitor

Here are three small stories, two from the field and one from home, two that were simply fun and one that leaves some questions.

One day in early February, I put on snowshoes with the intention of poking around in some meadows out the road. There was not a lot of snow, but the ‘shoes sometimes make it easier to walk over snow-covered grassy humps and bumps. And off I went, seeing a few tracks of mink, shrew, mouse, and weasel. A porcupine had wandered from the meadow down to the ice-covered creek and up the other side. Its trail intersected another trail, made by a river otter that had come upstream on the ice. In fact, there were two and possibly three otters, weaving in and out over the ice and finally coming up the bank. They went over a short stretch of meadow, under some trees, and down to a tiny, frozen slough. I decided to follow this trail as it went along the slough. The frozen channel got gradually wider, but I found one place where the ice was broken, perhaps by the otters. The edge of the opening was packed flat by otter feet, so it was clear that they had spent some time by this hole in the ice. What could they have found there? The trail continued down the icy slough, eventually joining the main creek again where there was some open water and a good chance of finding small fish. The total journey from creek-leaving to creek-joining was maybe half a mile. I think that these hunters knew where they were going and were just checking out another part of their home range.

I was having so much fun that I didn’t pay attention to my feet. When I finally happened to look down at my feet, I was surprised to see that I’d thrown a ‘shoe. So I back-tracked to retrieve that lost one, almost all the way back to where I’d picked up the otters’ trail. Having fun seems to be distracting!

One day in the middle of February, I wandered out into the Dredge lakes area, following a tip from a friend. After threading my way through a noisy passel of school kids, I went straight to one corner of Moose Lake. This is where we often see migrating trumpeter swans in fall, but this time I was looking for some patches of open water. I found them, under some snow-laden alder branches. The surface of the water was roiling periodically, so I knew something was going on in there. Peering closely into the dark water, I saw them: several big Dolly Varden moving slowly about in the shallows. I could pick out the white borders of their pectoral and pelvic fins, which are a good field mark. There was another big fish in the same bit of open water, a fish with no white on the fins and black speckles all over the body…probably a cutthroat trout. Dollies and cutthroats are known to overwinter in Mendenhall Lake and some of the accessible ponds in this area, where they hang out but feed little in the cold water. Why would they be in this spot? This area also sometimes hosts spawning coho in fall, so there is something special about it—and that’s the upwellings, where ground water burbles up through the sediments, bringing oxygen with it. Those fish are probably there to take advantage of the oxygenated water, which can be in short supply in some of these small ponds. As I watched, a dipper zipped out from just under the snowy bank and disappeared under the arching branches.

Dolly Varden. Photo by Bob Armstrong

On the way back to the trailhead, I started to duck under some low-hanging alder branches and saw something flit to the side. So I quickly looked up and saw a redpoll, perched not eighteen inches from my face. On the branch I had ducked under was a cluster of alder cones, a favorite food of redpolls. This bird scolded me roundly, so I apologized and moved on, while the bird went straight back to ‘his’ cones. I only saw one redpoll just then, but shortly later and not far away, I saw a whole flock of them at the seed feeders on my deck, cleaning up the millet seeds. Redpolls seem to show up around here sometime in February, most every year, making me wonder what they were doing in the earlier part of winter.

Common redpoll on alder cones. Photo by Bob Armstrong

My suet feeder at home normally attracts chickadees and juncos. But sometime in January I noticed other visitors. There were two very small birds that spent several minutes clinging to the wire-mesh suet holder and pecking at the suet. I was astonished to see that these were golden-crowned kinglets, birds that customarily feed on dormant bugs and spider eggs among the conifer needles. This was not a ‘one-off’ visit; they returned several times over the next few weeks (maybe more often than I noticed, given that I don’t spend the whole day watching from my windows).

Photo by Mark Schwann

This observation seems so unusual to me that I asked one of Juneau’s ace birders about it. I was told that, indeed, golden-crowned kinglets had occasionally visited their suet feeder too. Further inquiry via the internet revealed that this feeding behavior by golden-crowned kinglets has been reported, but very rarely, in Michigan and Tennessee, for instance.

Golden-crowned kinglets are so small (about six grams) that they lose heat rapidly (having a high surface-to-volume ratio), but they can’t store much fat. So they have to eat a lot each day, moving continuously through the foliage in search of tiny, sparse prey. They may save some energy at night by lowering their metabolism a bit and by huddling up together in sheltered spots, but the risk of going hungry and perhaps starving is significant. Given the high demand for energy, why don’t they visit suet feeders more often? And what got these few birds started on suet-feeding in the first place?

Snowy tracks

stories written on the winter landscape

Snowshoes crunched over deep snow. The sky was cerulean blue and the sun gradually crept around the mountain peaks. These were fine days to be out, seeing what we could see. We were especially interested in the tracks left by the wild critters as they went about their daily lives.

–A shrew left a long line of tiny marks by the side of a beaver pond. Short digressions led to tufts of grass or a buried stick, where spiders and bugs, slowed by the cold temperatures, might be found. Shrews only weigh a few grams and have a very high metabolic rate, so they have to eat almost continually. We often see their trails running over the snow and plunging into miniscule holes that lead under the snow blanket where prey might be found.

–Mouse trails are much less common. But one day we found a line of hopping prints that went out of the forest and across the upper intertidal zone to the most recent wrack line. The piles of tumbled rockweed might harbor small crustaceans, wayward seeds, or lost insects—all suitable for a snack. Another line of tracks went straight back into the shelter of the forest.

–Snowshoe hares had been busy in some areas. They too were looking for food, maybe willow or blueberry buds. But occasionally there were heavily trampled spots, very localized, as if there had been a dance or other social encounter. Popular routes became hare highways, packed flat along a small ridge or between two dense spruce stands.

–An otter had cruised for hundreds of yards along a frozen slough, making side excursions to visit (briefly) several beaver lodges. The deep trough left by its passage seldom came out in the open but usually stayed under the fringing conifers. Reaching the shore of a well-frozen lake, the otter abruptly turned around and went back the way it had come. The only open water on its route was a very small runnel below a beaver dam—a place not likely to hold good otter food.

–Across some thin pond ice, a great blue heron had gingerly minced its way from one patch of open water, at the inlet, to another, at the outlet. Taking very short strides on its long thin toes, it seemed to have been treading carefully. Little sticklebacks and juvenile coho, beware.

–In several places, we spotted narrow grooves on the snow surface, where a slim body had propelled itself on small feet. These wandering trails led to grassy tussocks, dove under logs, circled a pile of branches, disappeared under the snow and came out again. A mighty hunter was at work: a short-tailed weasel or ermine, whose coat turns white in winter, except for the tip of the tail. The short-legged, long body of a weasel is well-adapted for diving down vole tunnels and other tight places. However, that body form means that a weasel can’t afford to put on heavy layers of fat; the belly would drag when the weasel tried to run—not good for a hunter that has to keep moving for much of the day in search of prey. In addition to their small size, the body shape of weasels gives them a lot of surface area (where heat is lost) compared to the body volume (muscles and organs that generate heat), so they have a high metabolic rate to keep themselves warm. And that means they have to eat a lot. They eat mice and voles and small birds, and carrion when it’s available.

–Porcupines seem to wander widely, and we’ve found their trails in many places, often still distinguishable under a layer of new snow. One day we found a very fresh trail of footprints and even some quill-drag; we followed it along a little dirt bank until it disappeared over the edge. Looking down, we saw that a small log, sticking out parallel to the bank, had been wiped clean of new snow by the animal’s passage; the trail ended near the end of the log. Of course, we went around to an easier place to climb down the bank and investigated the trail’s end. There we found a deep burrow, with hairs and a few dried-up fecal pellets and a good barn-y smell, that ran into the bank for over two yards: a snug, dry den that had been used repeatedly for some time. Upon close inspection, that little access log had thousands of scratches, evidence of many balancing acts as the porcupine had ventured out and back.

Animals at play

a widespread pleasure

Any observant dog owners can recognize the invitation-to-play posture of their dogs, sometimes addressed to persons, and sometimes to other dogs. Surely none of us doubts that dogs love to play, with balls or sticks or each other. And cat owners watch their feline friends toss and chase toy mice, frolic with rumpled scatter rugs, and push pingpong balls under the couch only to fish them back out again. A favorite trick of some cats is ‘ambush’…running ahead of a person or another cat, hiding behind a door, and pouncing out as the victim passes by. Some cats and dogs even know how to make jokes, sometimes deliberately and mischievously misleading their humans or each other in frivolous ways. Of course, dogs and cats are domestic critters, which often have lots of time for frolicking, because they usually don’t have the need to find food or escape from enemies or find mates; the same is true for animals in captivity, which often need sources of amusement.

What about animals in the wild? Do they play too? Sure; especially younger ones, but adults too. Wolves and coyotes tussle and chase. They use the same play-invitation postures among themselves as dogs do; our late-lamented black wolf, Romeo, used to invite passing dogs to play. On-line sources offer plenty of examples: young elephants mud-sliding and mud-wrestling or macaques repeatedly leaping from a tower into a pool of water or….you name it.

Play behavior often has some utilitarian physiological functions, such as muscle toning or sharpening reflexes or improving coordination. It can also have useful social functions, such as learning the rules of interaction among members of a group (e.g., don’t play too roughly!) or establishing a dominance order. But play behavior would not be so common among critters if it weren’t simply FUN.

It took a long time for humans to recognize that animals, both domestic and wild ones, like to have fun. Having fun requires a degree of intelligence that humans have been slow to admit is found in animals—irrationally and wrongly preferring to think ourselves superior to everybody else.

Here are a few examples of animals that play, mostly from animals that we often see around here.

Young marmots box and wrestle on the threshold of their den. Bear cubs tumble and tussle with each other, sometimes engaging mama as well; so do beaver kits and young ones of many other species. Mountain goat kids sometimes bounce from ledge to ledge, apparently just because they can and it is fun.

Young humpback whales sometimes cavort, fluke slapping, pectoral slapping, and breaching, as if saying Hey mom, look at me! A local photographer watched one breach seventeen times in quick succession!

Photo by Doug Jones

We can see ravens having fun. They might fly up with a feather or some other object, and then drop it, only to swoop down and catch it again; or maybe a friend would dart in to snatch it away. Sometimes there is a game of keep-away: I’ve got a toy, you try to get it from me. We’ve watched ravens roll down a snowy slope, or slide like a toboggan, only to trot back up to the top and do it over again.

Crows play, too. There is an on-line video of a European crow sliding down a snowy roof while standing on a plastic lid; then it picked up the lid, went back to the top of the roof, and slid down again. What a hoot! (I couldn’t leave that one out, even though it is not local). Our northwestern crows sometimes dangle upside down from a branch, not reaching for anything nor avoiding something, just showing off. The biggest showoffs dangle on one foot: see what I can do! Then they may swing back upright with a wing-flap or two, or let go and try it again on a different branch.

Otters slide down muddy or snowy slopes. Some slide tracks are many yards long, and the otter then continued onward to wherever it was going. This is an energy-efficient mode of transportation—just push off and let gravity do the rest. But sometimes they are not really going anywhere, just down a small slope and back up again, to do it all over once more. Sometimes a whole slope will be covered with their slide marks. It must be fun!

Dall’s porpoises sometimes come to ride the bow wave of a fast-moving boat. A little group of them seems to appear from nowhere and together they ride that wave, sometimes for a considerable distance. Then they are gone, as suddenly as they came.

One day at Eaglecrest I found a place where ptarmigan had pranced around, leaving lots of footprints. These were interspersed with a number of slide marks, about three feet long, going down a little slope. We know that ptarmigan often glide to a stop when they come in for a snow-landing, leaving a short slide mark, but the marks I saw did not look like landing marks. They made me think of the otter slides, so I wondered if ptarmigan can play too. I turned up only one report, which says that flocks or family groups of willow ptarmigan frolic together, crouching low with head extended, jumping around, and flapping one or both wings. I would love to see that!

Beach-walking in late March

crow behaviors, elegant swans, boring (literally) clams, and a robbery on ice

What’s a restless naturalist to do, when most of the ground in covered with soggy snow and strong signs of spring seem reluctant to appear? Although the varied thrushes and juncos are singing, and the skunk cabbage has poked up in some places, some of us get a little impatient for more. One option for our edification is walking the beaches in hopes that something of interest will show up (it almost always does!).

On the way to Crow Point via the Boy Scout trail, small gaggles of garrulous geese flew from the river over to the far end of the wide, flat meadow. (Do they ever stop talking, except maybe when sleeping??)

Crows were beach-combing, dozens of them, all scattered along the line of the advancing tide, perhaps nabbing small prey that were activated by the onward rush of water.

Overhead, winging northward, were three elegant trumpeter swans. Although most trumpeters nest in the Interior, a few nest near the north end of Lynn Canal. It’s always a treat to see them, if only in passing, and that was the main ‘payoff’ for post-holing my way out to the beach. There had been strangely little foot traffic out this way, so post-holing was the only way to go.

On another day, for no accountable reason, I suddenly was possessed of the notion to look for mermaid’s purses. These are the egg and embryo cases of skates (relatives of rays and, more distantly, sharks). So I went to a beach where I’ve occasionally found them before, washed up on a big tide. Bingo! I found four of them: one black, dry, and dead, two much fresher, yellowish green, but ripped open, perhaps by an enterprising raven, and the embryos gone. The other one was intact, and I tossed back into the water, in case the embryos had survived their stay on the beach.

A short chunk of timber had washed up on the shore of Eagle Beach. It was completely riddled by smooth tunnels, about the diameter of a finger. Aha! Teredos had been at work. A.k.a. shipworms, for their unpopular habit of mining into wooden ships, teredos are really molluscs, albeit with a worm-like body. They can get to be over two feet in length, long, soft, and quite slender, with two very small, ridged shells at the front end. Those shells grind their way into wood as a teredo rasps its way along. The wood particles are digested, with the help of symbiotic bacteria that live in special cells in the animal’s gill. Teredos also eat plankton, which are inhaled by a siphon at the rear end of the body, and pass over the gill on the way to the mouth.

A teredo gets its start when a free-swimming larva finds a suitable piece of wood and settles down, attaching itself by means of byssal threads, such as one sees on mussels and other sedentary molluscs. The larva softens the wood at the attachment point, and then transforms into the adult shape and starts boring. Naturally, the tunnel gets bigger as the teredo grows and moves ahead.

Teredos are somewhat related to piddocks, another kind of clam that tunnels into hard substrates (and which have appeared in these essays before). Piddocks are clearly recognizable as a type of clam, but the stout shell is more curved and has ‘teeth’ along the edge. Piddocks use their burrows just for shelter and filter-feed on plankton, like ‘normal’ clams. A likely evolutionary link between teredos and ordinary piddocks is a group of distinctive wood-borers that use symbiotic bacteria to aid digestion, as teredos do, but the shells are more complex and substantial than those of teredos, a little more like the huskier ones of piddocks. Tunneling into wood (and rock, in the case of piddocks) is the way of life for a considerable array of clams, apparently, a surprising twist on our conventional view of more familiar, sediment-dwelling clams.

At Twin Lakes, the ice was dotted with open holes. A friend watched a river otter that was actively fishing—it caught and ate almost a dozen fairly small fish in a couple of hours. Then it caught a starry flounder; an eagle was watching and came down to snatch it away, but the otter saw the eagle coming and dove quickly, holding onto its prey. Later, the otter caught a big staghorn sculpin, hauled it out onto the ice, and began eating it, looking around for that thieving eagle. Down came the eagle, very fast, and ripped the sculpin right out from the otter’s feet. The otter dove beneath the ice, and the eagle had a good breakfast.

The moment before the theft. Photo by Jos Bakker

Thanks to Aaron Baldwin, ADF&G, for expanding my knowledge of teredos and their relatives.

Tracking at Eaglecrest

the usual suspects, plus a wandering otter

Eaglecrest was open, because it was spring break for the schools. So two snowshoers crept up the very edge of the groomed slope in order to (try to) stay out of the way of all the fearless little zoomers who were out to enjoy their holiday at top speed. A few of them apparently also enjoyed lunging over the edge of the groomed slope and plunging over drifts into the woods, so we kept a sharp eye out in case one came our way. Eventually we made it to the top of the slope and the upper cross-country loop, where things were calmer.

On this day we found many kinds of animal tracks—all the usual suspects, including red squirrels, snowshoe hares, weasel, mouse, ptarmigan, and peripatetic porcupines. Things got more interesting when we left the upper loop at its far end to visit Hilda Meadows. Just as we entered the first meadow, we encountered the distinctive and recent track of an otter, who had taken advantage of every little downslope to slide over the snow, leaving a smooth groove behind. This was an otter on a mission; it headed right down along Hilda Creek, which was mostly still buried in snow, into the steep canyon.

Not wanting to deal with the canyon, we were happily distracted by another set of tracks. Our best guess was that this creature was a coyote: fairly small dog-like footprints, all in a straight line. In the woods just above the string of small meadows, this trail paralleled Hilda Creek. The animal, like the otter, had a destination—with scarcely a deviation to sniff out a possible ptarmigan roost or to cross the path of a snowshoe hare, it bore straight down the valley. We’d lose the trail, sometimes, in the crusty snow under the trees, but we could always pick it up again in the next open space where the snow was softer. When the animal trotted down toward Hilda Point on the back side of Douglas, we settled for lunch in the sun.

On the way back uphill, we picked up the otter’s trail again where we first had found it, and back-tracked it along the creek. Near the top of the hill, we found that the otter had forsaken the creek in order to travel just inside the edge of the woods at a slight distance from the ski trail. When we reached the divide that separates Hilda Creek from the Fish Creek drainage (a swampy meadow in summer but now deeply buried in snow), we found the beginning of the otter’s trail. A hole in the snow led down to the very beginning of Hilda Creek, and the otter had emerged from that hole. So it must have slithered under the snow from the Fish Creek side, and presumably came up the Fish Creek drainage in its one-way journey. (And by the way, this is very near the spot where we found beaver tracks last month.)

We speculated that this might have been a male in search of a potential mate. Male otters range over many miles of stream and coastline and commonly overlap the ranges of several females. Mating is reported to occur usually in May (perhaps earlier in some years and some places), but the young are not born until the following winter or spring, because the embryo is not implanted in the uterus until long after mating and fertilization of the eggs. Delayed implantation is common among members of the weasel family. But it’s an interesting question: why do they do this!?

Visiting Gustavus

observations on geese, raptors, otters, and the effects of moose browse

One of the first things I noticed was a roadside muskeg in which the shore pines were in sorry shape, with many brown needles. Upon inquiry, I was told that these pines are infected by a fungus that causes needle blight. The fungus kills off mostly the older needles, so an affected pine has only small tufts of newer needles near the branch ends. A serious level of infection can kill the tree. Cool, wet weather favors the production of spores, which are spread by wind or rain-splash, and the spread of this disease. And that’s the sort of weather that has prevailed this spring, it seems.

A flock of several hundred white-fronted geese loafed peacefully in someone’s back yard, while an off-shoot group foraged nervously in a nearby field. These birds were on their way to the nesting ground on the tundra up north. They were enjoying an important way-station on their journey, where they can feed and rest.

A pair of Canada geese seemed to own a piece of pasture, apparently unruffled by grazing horses. But they reacted sharply when a little flock of other geese came in to graze. The small group of new arrivals was a mixed lot—mostly white-fronts, a couple of Canadas, and a sole snow goose. The residents paced back and forth, talking at the unwelcome visitors, who went right on grazing but did not venture much farther into the pasture.

The great outwash plain created by melting glaciers supports numerous stands of willows, most of which have been severely browsed by moose, such that they seldom exceed three or four feet in height. ADF&G has a long-term study of moose ecology and the effects of moose browsing, focused on a set of exclosures that prevent moose access. The willows inside the exclosures look markedly different from those outside: the inside willows are much taller and produce more catkins. The paucity of catkins on the heavily browsed willows may have extended effects, well beyond the diminished reproductive capacity of the willows themselves. Willow catkins are an important source of food (pollen, nectar) for queen bumblebees, which mate in the fall and overwinter in small burrows. In spring, they need to feed so they can produce broods of workers. Bumblebees are important pollinators of blueberries, beach pea, lupine, and many other flowers. So the obvious question is: Does moose browsing significantly reduce the spring food of queen bees, thus reducing their ability to produce healthy broods, and thus impairing the pollination success of various flowers?

Photo by Bob Armstrong

There may be other ripple effects of moose browsing. For example: Browsed willows produce fewer leaves and therefore less leaf litter below the shrubs. So we can ask if the reduced leaf litter affects the mosses, lichens, grasses, and herbs that constitute the ground cover. A lower number of leaves on the browsed shrubs should reduce their growth rates, because fewer leaves mean a reduced capacity to synthesize carbohydrates that provide energy. And one has to wonder if the cropped-off willows offer fewer nest sites and foraging surfaces for birds, leading to a lower density of birds than would occur in unbrowsed stands.

A male harrier coursed up and down the deeply incised channel of a tidally-influenced river that runs across the outwash plain; he was probably hoping to snag a shorebird or two. I heard snipe, high in the air, doing their flight display: as they swoop around, the rush of air over the spread-out tail feathers is modulated by the beating of the wings, producing a characteristic sound known as ‘winnowing’. Snipe winnow both on migration and on the nesting grounds, and most of these were probably still in migratory mode. I also think I heard a pygmy owl, tu-tu-tu-ing in the trees. A male robin carried a beakful of worms to his chicks, proving that the robins thought it was spring despite the raw, cold weather.

Another treat was the opportunity to watch three river otters exploring one of the inland ponds near Bartlett Cove. I suspect this was a family of a female with two of last year’s offspring, although there was not much difference in size. Otter families often stay together over a winter and into the next spring. These otters were well aware of our presence and kept bobbing up to peer at us. I was told that river otters are often seen as they travel considerable overland distances in Gustavus, visiting inland ponds (are there fish to be caught??) and returning to the ocean shores.

Mid January cold

bear bones, iris seeds, and frost flowers

Night-time temperatures at my house were subzero and not much better in the daytime, winds aloft were creating snow plumes on the peaks, and Lynn Canal was lashed to a frenzy of froth. But the SUN was shining gloriously and who could stay home on a day like that!

Bundled up to the eyebrows, I sallied forth on snowshoes with my favorite explorer friends. Although the snow was hard and crusty in general, there were soft spots, so we were glad to have big feet to spread out our weight.

Our plan was to revisit a small muskeg out the road, where years ago we had set an array of mist nets in order to sample the bird populations in the area. In that project, we opened the nets early in the morning and checked them every hour or so. One spring day, as we approached an opened net, we heard a loud ‘twang!!!’ and a brief thrashing of bushes. My field assistant said ‘That’s a bear!’ We dashed forward and, sure enough, there was a huge hole in the net where a bruin had popped the taut lines in its haste to remove itself from us. Not only that, there was a similar hole in the next net.

It was fun remembering that near-encounter but, alas, we didn’t quite make it to the designated muskeg. We had parked our vehicle in a safe area and tried to reach our destination via an untested route. This turned out to be a misery of jack-strawed wind-thrown trees. My twinkle-toed companions managed better than I did (no surprise there!), but eventually we all detoured down into some lower meadows where the going was easier.

In the meadows we found several things of interest to exploring naturalists. Otter tracks lead out of one tiny patch of still-open stream, across the ice, and then up into the snows. Coyotes seemed to have trekked hither and yon and spent time around some well-gnawed old bones. All that was left of a large animal was the pelvis and a section of spine. We spent some time dithering about the identity of the original owner of the bones and decided we needed to do a bit of research. Museum and internet resources finally led us to conclude that a black bear had died, perhaps not too far away, and its carcass had been scavenged.

Poking up above the snow were numerous stalks of the wild iris, long gone to seed. Close inspection showed that many of the seed pods still held seeds that scattered over the snow when the stalk was jostled. These seeds don’t have plumes or wings for dispersal on the wind, nor do they have sweet, tasty fruits around them for dispersal by hungry animals, nor do they have sticky hairs or hooks for latching onto a passing critter. Very curious! How do they get around and colonize new areas?

Back home again, after a hot shower and a restorative cup of tea, I noticed my cat gazing intently out a window. So I peeked out, and there was a young otter on the bank of my pond, rolling and grooming, cleaning and oiling its fur. Then it slid down under the ice through a small hole, roiled the bit of open water at the upper end of the pond, and reappeared at a new spot on the bank. There it chomped happily on whatever it had found, and dove back in. Later I noticed its tracks going across the snowy ice, presumably heading toward the next available hunting area. It must have repeated its visit, though, because later I saw another set of tracks on the same route. What a neat thing to have in one’s backyard!

Photo by Bob Armstrong

A few days later, the daytime temperatures had soared to about nine degrees. A little stroll on Mendenhall Lake gave us five mountain goats over on The Rock and some spectacular icebergs. The berg with the tall, sharp pinnacles had a thin flange in which the surrounding mountains and the sky were reflected at unusual angles, creating some fine abstract art (as noted by an admiring photographer). The most spectacular treats were the ‘ice-flowers’ that decorated the smooth ice of the inlet streams near where they joined the lake. Some of these delicate flowers were over five inches across. To a viewer with some imagination, some looked like flying birds, or dragonflies, or butterflies, or katydids. We could have spent the entire afternoon just looking at and photographing the fabulous array of forms.