February, 2006 Issues of Woodland Walkers Guide These are stories of the walks our collies have enticed us into taking as published in "The Home News", Spring Green's local paper. .

February 28, 2006

Perhaps you have seen "The March of the Penguins" an amazing movie that is currently being shown around the country and on video, featuring the emperor penguin. Winter arrives in Antarctica in March, and, surprisingly, this is the breeding season for these flightless birds. The female lays one single egg that she immediately transfers to her mate who tucks it into a warm pouch of feathered skin that is supported by his feet. She then leaves for the open sea to feed, traveling many miles across the frozen surface, while he egg-sits through two months of icy temperatures and wicked storms. When the egg hatches, he feeds it with stored food he regurgitates until the female returns with new supplies and takes over its care while he goes off to feed. The parents take turns brooding the infant and feeding until it grows large enough to join the other chicks on the ice and finally to take to the sea. This whole process is extremely precarious for the baby, and a friend commented on his surprise that such a process could sustain a population.

Many other creatures also manage to propagate with almost unbelievable strategies. Arctic terns perform spectacular migrations, every fall heading eastward across the Atlantic and down the west coasts of Europe and Africa to winter in the Antarctic Ocean. In spring they return north, following the East Coast of South and North America, a round-trip that can total 22,000 miles. There they lay two eggs on bare rocks, relying on their color and speckles for camouflage, and when the young fledge, all make the long migration back to Antarctica.

Then consider the bat: when the mother is going to give birth she must hang upside down in the cave and make a cradle with her wings with which she can catch the baby when it is born. The baby must then crawl from the cradle to her breast to begin nursing. The mother must then carry it about with her as she flies until it becomes too heavy.

This brought to mind another strange situation that occurs right in our own "backyard" with the lowly opossum. Opossums have not always been residents of Wisconsin, having expanded their range northward through the years from the southern states. A few years ago, we happened upon one that promptly climbed a nearby tree. Unfortunately, this tree was only about six feet tall, which meant that the animal could get no higher than eye-level, and it hung there looking pained the rest of the day. It was a funny little animal with soft, grizzled fur, a sharp snout equipped with mean-looking teeth, and a long rat-like tail. Ill-suited for a life in the cold, opossums' naked ears and tails are repeatedly frostbitten and often appear shortened, bloody and raw. Nevertheless, they survive and multiply.

Each female opossum is equipped with a roomy pouch in which to rear her young and a question has always been raised as to how the tiny naked babies manage to get there. According to David Attenborough's book, "Life on Earth", fable has it that that they are blown in. Opossums were said to mate by rubbing noses and the young were thought to be conceived in the female's nostrils. After a couple of weeks, the growing fetuses would irritate her nose and she would stick her head into the pouch and blow them out. Perhaps the theory arose because of the habit of the female of carefully licking the pouch clean to prepare for birth, but whatever the origin of that story, it is scarcely less credible than what actually occurs.

The female opossum has no uterus to house her growing embryos and, as each has only a tiny yolk sac to nourish it, they are expelled into the world after only twelve days. No bigger than bees, these blind pink mites are hardly more than two claw-like limbs and a mouth and they must find their way to the pouch or die. The female may produce as many as two dozen of them but a number never make it through the fur of her belly to the warmth and security of her pouch. Those that do, however, fasten on to one of the nipples, stimulating the mother to pump milk into its mouth. After two months, the babies will move out of the pouch and spend another four to six weeks on their mother's back. At this point, they are about the size of adult mice, and, despite the common illustration of the mother hanging out a row of babies from her tail, they climb all over her body. Soon they begin to fall off and join her in hunting for food. They will eat almost anything-fruit, seeds, and berries but also insects, reptiles, amphibians, and small mammals.

There are seventy-six different species of opossum in the Americas. The smallest is mouse-sized and does not have a pouch. Its young, no bigger than grains of rice, cling to the teat between their mother's legs and hang there like a tiny bunch of grapes. The largest is the water opossum that is almost the size of an otter that has webbed feet and swims. Its young develop in an elaborate pouch closed by a ring-shaped muscle that shuts the entrance like the drawstrings of a purse. The babies inside are able to endure several minutes underwater and can tolerate a concentration of carbon dioxide that would suffocate most creatures. The births of our local fawns, cubs, kits, and whatever are quite mundane compared to these, but many babies will begin appearing all around us before too many weeks pass.

February 21, 2006

This is the time of year when I find myself searching among the trees along the path for black cherries. What I am looking for, however, has little to do with the tree itself, but is a curled leaf still hanging from a branch that might contain the winter home of the promethea moth. The mature caterpillar wraps itself in a living leaf, first fastening it securely to its twig, and then spinning its cocoon inside, using the green foliage for both a foundation and for camouflage.

Should you discover one and choose to take it home, be sure to store it in an unheated garage or in the refrigerator, for if kept warm the moth will emerge prematurely. In May, you can bring it out, watching for the telltale moistening of the tightly closed doorway on the end that warns of the moth's imminent emergence. As soon as it hatches, return it immediately to the area where you found it, as mating takes place within a few hours and we want a new generation of these beautiful insects. The moths have four-inch wingspans and are unique in that males and females differ greatly in appearance. The upper wings of the male are almost black with narrow tan borders, while the female wings are a rich reddish-brown with wide borders.

I usually can spot a cherry tree by the black masses on its twigs, evidences of a very common fungal disease called black knot. The first stage of an infection is a small, light brown swelling that has a soft pulpy texture and becomes covered with a velvety, olive-green fungus growth. During the summer, the young knot turns darker and gradually encircles the twig or branch, and by fall, it becomes hard, rough and black. The fungus overwinters in the knots or in the infected wood surrounding them, and come spring, it produces spores in sacs contained within tiny fruiting bodies on their surfaces. These are ejected into the air during rainy periods and are carried by wind currents to green twigs of the current season's growth where they germinate and invade the thin surface.

Another way to find a cherry is to look for its distinctive bark. Young trees have a smooth reddish-brown surface on the trunks and branches, decorated with numerous horizontal marks. These are called lenticels, spongy spots that allow gas exchange between the atmosphere and the internal tissues. As the tree grows, the bark darkens and fractures into small plates that give it a patchy appearance; in fact, one writer thinks it resembles black cornflakes have been pasted onto the trunk. In the winter, the cherry is one of the easiest trees to pick out in the forest, because of this black rough flakey bark.

A new deposit of bark is formed each year and is made up of living and dead plant cells. The outer layer or cork is an aggregate of dead tissues and serves as protection against damage, parasites and diseases, as well as dehydration and extreme temperatures. It sometimes contains antiseptics like tannins, and rids the tree of wastes by absorbing and locking them into its dead cells and resins. Beneath this is the phloem, a network of elongated cells that die when mature and become ducts to carry food (particularly sugars) from the leaves where they are manufactured to wherever they are needed. Under this is the cambium, a watery layer only a few cells thick, that produces new cells for the phloem, and also for the xylem, the innermost layer which carries water and minerals from the roots up to the leaves.

Although some trees shed their outer bark regularly, most retain several years' growth and the bark appears quite thick. Patterns formed by bark are often very unique and distinctive, and as a result, some trees can be readily identified using them. Paper birch is probably the easiest, as its chalky white bark separates into papery layers, revealing pale orange when first exposed to the light and becoming dark and rough on old trunks. River birch has cinnamon to red-brown curling bark, which presents a ragged appearance, while the bark on older trees becomes darker and deeply furrowed. Yellow birch has a very fine shredded bark that peels into small strips.

Most white oaks are light gray in color and have bark that appears slightly blocky in texture. Black oak has bright yellow inner bark covered with rough black outer bark broken by deep fissures. Northern red oak has smooth grayish bark when young but darkens considerably with age and develops flat-topped ridges. The bur oak develops corky areas on its smaller branches and has bark that is particularly resistant to fire.

The shagbark hickory can be readily identified by the numerous long, grayish strips of bark that peel off from the main stem and are usually attached at the middle and loose at both ends. Black walnut displays a dark brown, deeply furrowed bark in the winter months. The bark of the basswood varies in color through the grays and brown, and has pronounced vertical, flattened ridges. Aspen bark is smooth, thin, yellowish green to nearly white with wart-like spots, but darkens and becomes thickened and fissured with age. Take a walk and look around you at the trees. Their bark is really amazing stuff, and don't forget to keep an eye open for a cocoon.

February 14, 2006

When I studied biology in school, I was fascinated with the collection of bird skins on display, marveling at being able to examine the tiny creatures closely. I could see the details of each feather and identify differences in the various species, but I was distressed by the knowledge that so many were killed for my education. As an adult I found I could have the same experience by taking photographs of the living birds, with the added advantage of capturing their postures and attitudes. However, I found it required extensive and expensive equipment to get the pictures I wanted, as my snapshots often resulted in images of just teeny specks.

Enter the digital camera! Suddenly, not only were we able to take endless numbers of shots that we could view and edit as soon as we downloaded them into the computer, but with the zoom lens we could get pictures that were beautiful and detailed. I could snap close-up shots of the tamer birds that allowed me within the camera's range, while husband Bill could take marvelous pictures of small birds from as far as 50 ft. and larger ones up to 200 ft. with his digital camera to which he had affixed a spotting scope. We now have an extensive collection of photographs to which we continually make additions, and it has become a captivating hobby for both of us.

Bird photography can be quite a challenge, however--first to find the subjects, and then to make them stand still long enough to get a picture. The ideal method is to have them come to you, and food certainly is the easiest and least expensive attraction. A bird on a feeder lacks something, however, and it gives more natural pictures to arrange a convenient perch nearby. Branches or twigs that have interesting bends or bark are excellent, but make one particularly convenient for the bird so that you can predict where it will land and be prepared. Typically, it will stop only briefly before continuing on to the feeder, so you will probably have only a second or two to make the shot. Also, nothing ruins a good photo more than a distracting background so it is best to place your perch in a relatively uncluttered area if possible.

Ground feeding birds will require perches as well, and a log or old stump can be interesting. These birds seem to be less flighty and will pose for longer periods, but it helps to offer plenty of goodies. Some photographers report that they drill wells on the logs to hold seed, making sure to place them where they are not visible to the camera. Offering an assortment of food will increase the number of species that visit your feeders, and adding suet, peanut butter, bits of fruit, and insects such as mealworms to a variety of seeds will give the greatest chances of success.

Water, particularly during dry periods, will attract many birds that will not come to feeders. We have identified and photographed some forty species at the small garden pond and waterfall outside our back door during the summer months. Here the background is always natural, and although the light is often a problem when the overhanging tree foliage darkens the area, we capture many of the birds before the leaves emerge. Natural light is best in early morning and late afternoon, and we are experimenting with finding a flash system that will fill in when needed. Best times are just after sunrise and before sunset when light is soft and color is often enhanced.

Once you have arranged your offerings, you must find the best way to get close enough to the bird to photograph it. Your house (or a shed or garage) can serve as blind, but you must not allow the birds to see any movement. Use openings if possible, but if you must shoot through a window, be sure it is glazed with modern glass, is very clean, and any draperies or blinds open just enough for your camera. Reflections on the glass can also cause problems, particularly with a flash, but the big advantage is being able to be comfortable during winter months. Another possible blind is your car, as many birds are used to seeing vehicles and ignore their presence.

We have found that a spot of light in a bird's eye is important to give it personality and life, and this can be particularly noticeable in a bird with a black eye on a black face. Unless the light is perfect, there will be no detail and all that is often seen is a black, featureless patch. One way to deal with this is to keep the sun at your back, although an electronic flash will also reflect back and do the trick.

Digital cameras come in all shapes and sizes, and new ones continually appear on the market. My current favorite is an Olympus 750 with a 10X optical zoom, while Bill uses a Nikon 990, that we acquired from eBay, with a 50 mm spotting scope attached. His setup requires a tripod and is more bulky and inconvenient to carry around, but allows him to take excellent frame-sized photographs of small birds at a distance, while mine has a limited range but is easy to pack. If you are considering getting a digital camera to photograph birds, get one that has the longest optical zoom length possible, or invest in a larger one with additional lenses. The results will please you.

February 7, 2006

I've written previously about our continuing struggle to determine what plants should dominate in our remaining prairie remnants, and much of our winter labors are expended in this effort. We try to encourage what we consider to be suitable plants, but many of the others that are less desirable do their best to keep not only a toe-hold, but spread as far as they can. Notable among them are the red cedar, sumac, prickly ash, and assorted berries. The problem is that they don't play fair, utilizing a variety of stratagems that are very difficult to counter.

Take red cedar, for instance. The tree offers untold numbers of tasty fruits to birds and animals that happily eat and then deposit the indigestible seeds all over the area. These seem to sprout readily and grow quickly, providing a constant supply of new seedlings that become trees before we know it.

Even worse are other plants that not only spread lots of seeds, but manage to clone themselves as well. If you have looked closely at a grove of sumac, you will see that it often takes the shape of a mound. The oldest plants are in the center and are taller than those around them, while younger, shorter plants have sprouted from underground runners called rhizomes around the edge. Eventually, each runner withers away, leaving a completely independent sumac that is genetically identical to the sumac beside it.

Staghorn and smooth sumac are both native species with coarse, sparse branches. Plants may be either male or female, and the tiny greenish-yellow female flowers produce cone-like clusters of crimson berries that remain throughout the winter. Granted that these have their uses as they provide an important emergency source of food for skunks, songbirds, grouse, deer, and rabbits, and Native Americans and early settlers made a lemonade-like drink from them. The bark, especially of the roots, was found to be very rich in tannin and was used in tanning skins, and European colonists reportedly made ink from parts of the plant. The staghorn got its name from its winter looks, as its bare, widely forking, hairy branches resemble deer antlers "in velvet". It, and smooth sumac will invade almost any open sunny site, regardless of moisture (up to a point) and soil type, and although both form extensive, dense groves of clones, at least their seeds do not seem to germinate readily.

Prickly ash is also a shrub or small tree that forms thickets by reproducing from rhizomes. It not only has the added disadvantage of being covered with nasty thorns, but it also seeds itself extensively. The ground near any of the adult plants is usually covered with sprouting seedlings as well as clones, and it requires careful searching to root out every potential tree. Male and female flowers appear on separate plants in small, greenish clusters in April and May before the leaves, and the fruit is a red "drupe" about the size of a small pea. Being in the citrus family, its taste first reminds one of tart orange rind, but upon chewing, it quickly numbs the mouth--hence the name "toothache tree," reflecting an early use. The only good thing I can find to say about this nuisance tree is that I sometimes find the larvae of the giant swallowtail butterfly on its leaves.

Blackberries, which have a three-year life cycle, have a different method of cloning. In the first year, the cane establishes itself, during its second year, the cane flowers and bears fruit and seeds, and in the third year, the long cane arches down to the ground, usually developing roots and making a new plant. Black raspberries perform a similar cloning act, but they achieve it in only two years. The specialized roots that allow the cane tip to anchor itself are called adventurous roots, These can form from non-root tissues, and usually arise from divisions of cells in the stem, although they can also come from auxiliary buds hidden in the bark or even from some leaves.

Roots operate by means of osmotic pressure, enabling plants to acquire water from soil that may look and feel fairly dry. In typical soil, water is available to plants mostly as a thin film surrounding every microscopic soil particle. To take advantage of this moisture, active sections of a root commonly possess untold numbers of single-celled projections called root hairs, which greatly increase the absorbing surface of the root and achieve much greater contact with soil particles. Root hairs absorb this water and then, molecule by molecule, water diffuses through the root-hair's cell membrane, flows toward the main roots, and then is carried upward to the rest of the plant by capillary action.

One interesting thing about root hairs is that each hair is essentially a long, slender, practically-invisible bulge from the side of a single cell embedded in the root's outer surface. In a classic study by H.J. Dittmer, a single rye-grass plant growing about 20 inches high and consisting of a clump of about 80 shoots, was found to have 380 miles of roots, and this included 14 billion root hairs! He reported that if all these root hairs had been split open and spread flat on a floor, their combined surface area would have covered more than 4,000 square feet, and all this root-hair surface-area was absorbing water for that single clump of grass. With all these forces working against us in these hardy and determined plants, what chance do you suppose that we have to hold back their expansion?