An ordinary walk at Crow Point

The walk around Crow Point near the Boy Scout camp and the Eagle River estuary is easy. Sometimes there is lots of wildlife activity, but on this day, things were very quiet. A stiff north wind was whipping up whitecaps on Lynn Canal and, with an eighteen-foot high tide, the surf was pounding the shore. It was easy to see how those big beach logs get moved around and the sand gets chewed away from the raised, grassy bench. Off to the west, the snow-clad Chilkats gleamed in the sun.

We plodded along the upper edge of the sand beach, detouring up into the grass where the surf came in too close. With a little work, we could discern otter tracks amid a plethora of dog footprints. Our jacket hoods were up and our backs were hunched against the sharp, cold wind. Not until we rounded the corner to the south-facing beach did we find comfortable conditions and, at last, a little wildlife.

Here, out of the wind, dozens of gulls (glaucous-winged, mew, and a few herring gulls) fossicked around at the water’s edge or loafed, in between quick jabs at something edible. As we approached, they all shifted away along the beach, but when we perched quietly on a log, they moseyed cautiously back, until they were almost directly in front of us, maybe twenty feet away. Whatever they were finding was still too small for us to discern.

We three bumps on a log were inspected, at a distance, by two Pacific loons, a horned grebe in winter plumage, and a wandering sea lion from the Benjamin Island haulout. Overhead, a raven checked us out but didn’t come in for handouts. A raven visit to a beach picnic used to be a regular entertainment here but has become less frequent, making us wonder if some people have made them unwelcome.

Making our way back around the perimeter of the big, flat meadow, we discovered several rototilled areas where bears had foraged, probably for angelica. We find these digs here every year, it seems, begging the question of how there can be any angelica plants left.

Photo by Bob Armstrong

We found two small wild rose bushes, leafless but bearing tiny crops of fruit. In the slanting sunlight of mid November, even three or six rose ‘hips’ made a conspicuous display of gleaming red globes. Who eats these fruits? Humans sometimes use them, after suitable preparation, as ingredients in tea, jam, and syrups, and as a source of vitamin C, but do bears or birds eat them??? Every rose hip I’ve opened up is filled with stiff bristles around the seeds, and these might be rather prickly in the mouth.

Several buffleheads paddled quietly in the slough beside the river, nicely sheltered from the wind by the tall grasses. Even when our walk-by made them nervous, they didn’t leave the lee of the upwind side of the slough.

On the bank beside the trail between the beach and the parking lot, we noted a large mat of a green and apparently very happy liverwort with strap-like ‘leaves.’ Liverworts can be a big frustration for field naturalists, because many of them are nearly indistinguishable (in the field) from mosses. But this one was not so, and we could be sure of its general identity. Even better, we could later track down its probable species. It is reported by a local botanist to be common around here, even though our favorite plant field guide doesn’t show that it lives here.

A rather ordinary walk, nothing really surprising or wildly exciting. But perhaps that depends on one’s concept of ‘ordinary.’ I think that Juneau ‘raises the bar’ for defining the word ordinary! The gleaming Chilkats are ordinary?? Do we take so for-granted a flight of geese seen against a blue sky?? Or the fact that we can see evidence of otters and bears (and often other beasts as well) as one strolls along? There are lots of places where one can’t do anything of the sort. ‘Ordinary’ is all in the eyes and minds of the beholders.

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How to be an herbivore

Herbivores are vegetarians, although some snack on meat upon occasion (beavers eat some salmon, deer sometimes eat birds!). Herbivory typically refers to the eating of living plants: leaves, shoots, stems, roots, and flowers. Subsisting on plant materials is not easy, because so much of a plant consists of cellulose and sometimes lignin—the walls of plant cells are generally made of these indigestible materials. In comparison, subsisting on meat is relatively easy, because the cell walls of animals are readily broken down and digested. Although seeds are plant parts, seed-eaters are a special category, because they deal with highly nutritious, relatively easily digested material, made by the plant to nourish the enclosed embryo.

Plant-eating animals have evolved several principal ways of dealing with their difficult diet. Many kinds of insects have mouthparts that pierce cell walls, so the consumer can suck out the cell contents without ingesting all that cellulose. Other plant-eating insects chew up high volumes of plant parts and just excrete the unwanted material. A few can digest cellulose to some degree. (Insects that eat wood and other dead plant material usually depend on symbiotic protozoans or bacteria in their guts.)

Vertebrates face the same problem of dealing with cellulose and, being too large to suck out cell contents, they solve the problem in various other ways. Only a few have simple digestive tracts that pass food quickly without metabolizing much of the cellulose: pandas and some odd South American birds called plant-cutters chew up leaves and shoots in vast quantities (much more than expected for their body sizes); the plant cutters and perhaps the pandas depend on unusually high rates of enzyme activity to extract nutrients from their fibrous diet.

Other vertebrate herbivores generally rely on micro-organisms to help digest cellulose. Some house their digestive microbes mainly in the front part of the digestive tracts, where there are typically several chambers in the stomach or esophagus. The action of the microbes is called fermentation, and animals that have their symbiotic microbes in the front part of the digestive tract are called foregut fermenters.

Animals that are foregut fermenters assist their microbes by producing lots of saliva containing phosphorus and other chemicals that nourish the microbes. The microbes get digested too, so they have to reproduce rapidly to maintain a working population in the foregut. Although some fluids and small particles bypass the microbes and go right into the rear part of the gut, much of the ingested food is processed by the microbes before passing on down the gut. Some foregut fermenters regurgitate their food and chew it again (“ruminating”), before swallowing it once more and passing it into the rest of the digestive tract. Foregut fermenters often have some microbial fermentation in the rear part of the gut too.

Foregut fermenters include kangaroos, tree sloths, certain monkeys, camels, and the ruminants (deer, cattle, sheep). One really weird bird, the hoatzin of South American, is also a foregut fermenter, with such a large fermentation chamber it can hardly fly. (Parenthetically, but interestingly, baleen whales are foregut fermenters too, only they digest chitin from the shells of krill.)

Most vertebrate herbivores house their helpful microbes in the hindgut, in the large intestine itself or commonly in a special out-pocketing called a cecum, which is very large in some of these herbivores. The contents of plant cells are digested and absorbed in the small intestine, and the cell wall material is sent to the hindgut for fermentation. There the resident microbes extract or make various nutrient but don’t greatly increase digestion of fiber. But then what? How do these herbivores take advantage of their symbiotic microbes and the useful nutrients they produce in the hind gut?

Hindgut fermenters typically produce two kinds of feces, separating the gut material into two fractions, one well-digested but full of microbes and still nutritious and the other fibrous and nutrient poor. The nutrient-rich and microbe-rich feces can be distinguished by texture or smell and are ingested. Research has shown that coprophagy (eating feces) is truly essential to growth and good health in these animals.

Hindgut fermenters are prevalent among all groups of herbivorous vertebrates, including amphibians, reptiles, birds, mammals, and even some fishes, but all animals that depend on coprophagy are relatively small (less than about one hundred pounds).

Parenthetically: before you wrinkle your nose and say ‘yuck’ at the thought of coprophagy, think about this: Ambergris is a waxy material excreted by sperm whales, possibly to aid the gut passage of squid beaks, which are hard and sharp, and might rip up the gut membranes (but other squid-eating whales don’t make it…). This material reportedly smells fecal at first but eventually acquires a pleasant odor. It has been important for the perfume industry and certain medical uses and reportedly has sometimes been considered to be a delicacy for human palates. Eating sperm whale poop?????? Really! Now you may wrinkle your nose!

Even with special digestive adaptations, some plant-eaters maintain a relatively slow life style. Koalas, specializing on eucalyptus leaves, have low metabolic rates and sleep a lot. Porcupines and tree sloths have slow metabolisms and are typically quite slow-moving. Beavers sit out the northern winter in their lodges, eating little (except the young ones, which eat cached twigs, and keep growing) and staying warm. Manatees and dugongs have low metabolic rates and take days to slowly process their plant food. These observations beg the question: why aren’t all plant-eaters slow?!

Bird Brains

When someone does something stupid or behaves in a scatter-brained way, we may jeeringly, scornfully, call that person a ‘birdbrain’! But wait a minute: is that epithet really accurate or fitting? Consider some of the amazing things that avian brains accomplish!

Chickadees, nuthatches, and corvids (jays, crows, ravens) cache food and can remember hundreds and thousands of cache locations for weeks and months. Clark’s Nutcrackers (another corvid) spread their hidden stores of pine seeds over many square miles and can retrieve almost all of them, even after several months. That’s a lot better than what many humans could do, even with practice.

Crows of various species have shown considerable ability to figure out problems that require insight. New Caledonian crows invent new ways of extracting a food item, by using a sequence of tools in the appropriate order. They can do this without practice, sometimes even inventing tools. For instance, one of these crows figured out how to use a little hook to extract a tiny food basket from inside a container, and when such a hook was not provided by the experimenter, the crow made one from a straight piece of wire. European rooks invent tools too and use them in novel situations; a rook quickly figured out that it could raise the water level in a beaker by dropping stones into the water, thus raising a floating food item up where the crow could get it. Crows in Japan drop nuts in front of traffic, letting the vehicles crack them open; if the vehicles miss a crow’s prize item, the crow may pick it up and drop it in the traffic lane again. This is a relative new trick, just developed a couple of decades ago, and it shows that the birds are capable of insight.

Some birds (parrots) are capable of reasoning by analogy. For example if items A and B are different from each other, but C and D are identical, these birds learn the concept of ‘different’ and ‘same’ and can apply it to a novel situation, recognizing that items W and X are different but Y and Z are the same. Thus they show some ability for abstract reasoning. I know some otherwise apparently normal humans that would have trouble doing that!

Many birds are capable of observational learning—watching another bird do something and copying what they see–and some birds (parrots, some songbirds) can copy sounds or songs too. Many mammals cannot do this. Certain birds go on learning new songs all their lives: canaries learn new songs (and grow new neurons to do it) every year, replacing the old neurons and songs, while mockingbirds and parrots can go on increasing their repertoires throughout their lives.

The tiny brain of a hummingbird (smaller than a pea) is capable of guiding the bird on extended migrations, up and down the Pacific Rim in the case of our rufous hummer and over the Gulf of Mexico in the case of the ruby-throated hummer. No mean feat!

All that is not to imply that bird brains are like human brains. Like our brains, bird brains do have right and left sides, which function differently. But birds have considerably bigger brains, relative to body size, than humans do. As in all vertebrates, bird brains are divided into three parts (fore, mid, and hind) and in both birds and mammals, it is the forebrain that is specialized for ‘smarts’. In birds, however, it is the so-called hyperstriatum (an inner part of the forebrain) that provides what we call intelligence, whereas in mammals it is the cerebral cortex (the outer part of the forebrain). (But contrary to what you might read on Wikipedia, bird brains are NOT located in the thorax!)

So, the bottom line here is that bird brains are really not to be scoffed at. Perhaps they should even be admired for some of their amazing accomplishments! Humans have had a hard time learning that other animals have talents, skills, wit, and emotions, worthy of respect, even though Darwin paved the way over a hundred and fifty years ago. We can be very slow learners, despite our much-vaunted gray cells. Perhaps there is a lesson there!

An extended day…

When the day began, we only intended to stroll to Outer Point on Douglas in search of the spotted coralroot orchid. Rubber boots were needed for crossing Peterson Creek, but by the end of the day, I was wishing I had a change of footgear. Searching through the understory for some time, we finally noted some small spikes sticking up out of a old rotten log–a limited success, because they were not yet blooming. We’ll have to wait a week or two to get a good picture of the pinkish flowers.

Because the tide was low, we then ambled out along the long storm berm to Shaman Island. Dodging the war games of some rambunctious kids, I learned where to look or some super-sized barnacles down near the low tide line. I’d like to know more about these—are they a different species from the usually types that cluster all over the stones and mussel shells, or are they just unusually happy? (In Chile, where I spent many months in the austral springs, the giant barnacles are considered to be a delicacy!)

Photo by Bob Armstrong

By now, it was well past noon and both of us felt hungry and a little frail. But we decided to go up the Eaglecrest road to check on a willow tree that has been much used by sapsuckers, which drill sap wells in the bark and lap up the sap and any stuck insects. We found the tree, and a sapsucker arrived while we watched, so all the recent construction at this spot hadn’t destroyed the bird’s favorite lunch stop.

Best of all, a group of Plein Rain artists were gathered nearby, enjoying a chilly workshop with a visiting artist—and they had food! By managing to appear really wan and wobbly, we persuaded these very kind folks to feed us too! Many thanks to these good Samaritans! And the art work spread out along the walkway was very nice too—Juneau talent at work!

Reinforced by serendipitous sustenance, we decided to check out a bird nest down along Fish Creek. A short walk by the stream and a brief sit-down on the bank let us get a good look at the nest. At this point the sit-down was welcome, because my feet do not like walking or standing around in rubber boots.

Returning to the car over the new footbridge over Fish Creek, we hailed two other friends, also out for a walk. They had recently seen a female common merganser with eight chicks on one of the nearby ponds, and some of the little ones were riding on mama’s back. We inspected a beaver lodge and some recent beaver cuttings, and enjoyed a long chat.

Thus the day turned out to be much longer and far more social than initially planned. But that is not a complaint (even though my feet said otherwise…)!

 

The next day, three friends hitch-hiked a ride out to Portland Island. The crabapple trees were blooming, although they looked decidedly weather-beaten. The oystercatchers and Arctic terns had eggs and were incubating. Their nests in the sands of the upper beach are nothing more than a saucer-shaped depression, very difficult to spot and easy to crush accidentally, so it is not a good place to walk. One oystercatcher was implanted with a tracking device a few years ago, in order to learn a bit about migration patterns, but she is back again, nesting in almost the same location as in previous years, and incubating three eggs. For some reason, the wire antenna extended from her backside does not seem to interfere with mating or anything else. We got too close to her nest, and she put on a great broken-wing act, with much shrieking in protest. We left in a hurry!

The density of song sparrows was notably high. Some were feeding fledglings, which shrilled their begging calls from deep in the dense vegetation, and others were still feeding nestlings. Because they were still singing frequently, I suspect that they intended to start second broods.

A gang of gulls loafed around on a sandbar. They seemed very nervous, lifting off en masse every few minutes. Some of these flights were probably in fear of an eagle flying by, even if the eagle was far away and seemingly intent on something in the distance. Perhaps the gulls know from experience that eagles can look deceptively innocent but quickly become malevolent.