December 2005 Issues of Woodland Walkers Guides These are stories of the walks our collies have enticed us into taking as published in "The Home News", Spring Green's local paper. .

December 27, 2005

Fifteen, sixteen, seventeen The blue jay sitting on the edge of into the seed basket dipped its beak into the pile of goodies, each time coming up with a fat sunflower seed and then tipping back its head and swallowing it. At the count of twenty I thought surely the bird must have taken its fill, but it only jumped down into the center of the basket and continued without a break. Hard as it might be to believe, that bird ingested 60 seeds before flying off, answering the question as to why the seed supply always seemed in need of replenishing.

Carter Johnson and Curtis Adkisson, in their article, Airlifting the Oaks, (Natural History 10/86:41-46) studied the oak planting abilities of eastern blue jays. They kept track of 50 jays and found that they gathered and cached 150,000 acorns in 28 days, about 110 acorns per day for each bird. Blue jays are energetic hoarders, storing acorns and other booty in cracks and crevices of tree trunks or in loose soil where many that were not later eaten would subsequently sprout. A blue jay can carry up to five acorns (or evidently 60 sunflower seeds) at once by swallowing and carrying them in the upper part of its large, expandable esophagus. The hoard is then regurgitated at chosen storage sites around the area. Blue jays are members of the crow family and are highly intelligent with good memories, and they usually retrieve most of the stored material. They eat mostly acorns, nuts, and seeds with a few insects and small vertebrates thrown in, and are not above feasting on eggs and nestlings of other bird species if available. Blue Jays are adaptable and will take advantage of almost any food source, eagerly coming to backyard bird feeders.

It is always hard to remember that the bright blue on these birds is produced by a trick of the light, rather than an actual pigment. Most other bird feathers get their brown, black, and gray colors from melanin, the same dark biological pigment that affects human skin, or carotene that shows as yellows, oranges and reds. Both kinds of pigment act to absorb certain wavelengths of light and reflect the rest, causing them to appear to our eyes as color. A blue jay's feathers do have melanin but it is below the surface under a layer of bubble-like cells. These bubbles reflect and scatter blue light waves, while the melanin absorbs the other colors of light. That is why the blue jay's feathers look blue in sunlight but a darker gray-blue in the shade, as the melanin is more visible. White is also a structural color; that is, we see feathers as white when their structure reflects back to our eyes the full range of the light wavelengths that strike them. When a white feather is observed under a powerful microscope, the surface resembles cut glass or snow. It lacks melanin and contains many more air bubbles than does a blue feather.

In contrast to the melanin that can be manufactured in their bodies, birds must obtain red, orange or yellow carotenoid pigments from the seeds and berries that they eat. These pigments are manufactured only by plants, and when the bird acquires them through its food, they are dissolved in fat globules and then deposited into their growing feathers. In the 1800s, this process led to the captivity of untold numbers of the beautiful red bird we call the northern cardinal. It was found that these colorful birds would adapt readily to life in an aviary if introduced as nestlings, and would sing several months of the year. They became much-sought-after cage birds, and thousands were trapped in the south in the winter and sent to northern markets, and thousands more were sent to Europe. Cardinals are noted for their loud, clear whistled songs, and even the females will sometimes join their mates in singing. These songsters were highly valued, but it was soon discovered that their colors faded in captivity and it was only later that it was discovered that this was due to the foods they were routinely fed. This trade was halted, fortunately, with the passage of the Migratory Bird Treaty Act of 1918.

The cardinal was originally found only in the southeast parts of the country, but its range has expanded northward in the last 100 years. In 1886 it was seen only occasionally north of the Ohio River but by 1895 it had reached the Great Lakes and by 1910, it was discovered in southern Ontario. Since the food supply is the major factor in winter survival for birds, it may be our hobby of backyard feeding that has allowed it to survive our Wisconsin winters and grace our lawns and trees.

The image of a northern cardinal perched upon a snowy branch is so striking that it is used extensively on Christmas cards, calendars, clothing and all sorts of holiday decorations; in fact, I would be willing to bet that I am not the only one who has exclaimed about the beauty of such a sight outside the window this week. Add to that the blue of the jays, the gold of the finches, and the bobbing red heads of the woodpeckers, and winter loses much of its depressing drabness. A happy new year to you all!

December 20, 2005

In our hustle and bustle this week, few of us are aware that another important date is imminent. The winter solstice occurs during the morning hours of December 21st, that time when our hemisphere is leaning farthest away from the sun, and therefore the sun makes its lowest arc in the sky and we have our fewest hours of daylight. Solstice means "standing-still-sun", and ancient and not-so-ancient people considered it a very significant time of year.

Egyptians believed that Ra, the sun god, became sick and weak each year, and at the solstice, he would begin to recover. They made it a time of celebration that symbolized the triumph of life over death, and they filled their homes with greenery. Plants and trees that remained green all year had a special meaning for many of the early peoples, and in many countries it was believed that evergreens would keep away witches, ghosts, evil spirits, and illness.

As the Christian message was spread across these lands, many of the pagan festivals and customs were given new meanings. Tradition credits Martin Luther as being the first to attach burning candles to an indoor tree, in an attempt to recreate the sight of shining stars through an evergreen forest. A 1605 diary found in Strasburg describes a tree decorated with paper roses, apples and candies, and Germany is credited with starting the Christmas tree tradition, as we now know it.

In the New World, the Puritans believed that decorated trees desecrated the holy day, and as late as the 1840s, most Americans still considered Christmas trees as pagan objects. Today, however, the tree is seen as a symbol of the Christmas spirit by most Christians and a fitting center for family and religious gatherings. It is interesting that it is non-Christian groups in America who now object to calling it a Christmas tree.

There were few native evergreen trees in southern Wisconsin suitable for this use until white men planted them, although there were tamarack or larch, deciduous trees that lose their needles yearly, and arborvitae and red cedars, both trees with small scale-like leaves instead of needles. Conifers were the dominant tree farther north, however, and pines and spruce were eventually established throughout the state.

The distinctive characteristic of conifers is not that they are evergreen and bear needles, but that they bear cones instead of real fruits. They are often thought of as a step between spore producing plants such as mosses and tree ferns and flower-producing plants, as they produce flower-like pollen and seeds, but they don't have real flowers. Small, bright yellow stamens emerge from male cones among the needles and often hang down in clusters, producing pollen that is carried by the wind to the tiny female cones.

Like the blossom on a flowering plant, the cone is actually a highly modified branch; unlike the flower, it does not have sepals or petals but consists of a central axis surrounded by overlapping, scale-like, modified leaves. The numerous scales of the male cone bear pollen sacs and those of the female cone bear ovules in which egg cells are produced. In the spring when the pollen is released, the scales of the female cone separate slightly and exude a sticky substance that traps the airborne pollen grains and draws them down into the ovule. The scales then close to protect the developing ovules and it is usually a year or two before the seeds have developed. At that point, the scales again separate, allowing the mature, winged seeds to be dispersed. The female parts of junipers, tamarack, and yews differ in that they produce fleshy cone scales that fuse to form a berrylike structure.

Most conifers have a central trunk and a tiered or whorled arrangement of branches, and except for the few deciduous types, the conifers are evergreen, meaning that the leaves function for more than one season. Conifers have proved to be very successful survivors. Some grow to heights as great as 200 ft. and may reach an age of more than 3000 years, while a few bristlecone pines are thought to be some 4000 years old.

As we decorate our homes with Christmas trees and evergreen boughs this week, we will be joining a long tradition of believers. In the words of Tiny Tim: "God bless us, every one".

December 13, 2005

After experiencing the hilarious and energetic performance of the River Valley Players on Saturday evening, it was a sudden change to emerge into the quiet of the snow-blanketed street. The muted sounds, the colored lights, the soft flakes falling-all made the scene reminiscent of a Christmas card or perhaps the set for "It's a Wonderful Life". I hope you have taken the time to look closely at the snowflakes that have been falling all this week. It is true that their arrival has required much shoveling and negotiating icy walks and slippery roads, but the snow crystals have been unusually large and beautiful and have transformed the landscape.

It was Robert Hooke in 1665 who first examined snowflakes under the newly invented microscope and made sketches of what he saw for his book, Micrographi. These drawings were the first to duplicate the intricate symmetry of snow crystal structure, but it remained for Wilson Bentley to capture their images on film in 1931. He published his famous book, Snow Crystals, which contained more than 2000 photographs and is still a classic on the subject. Then, Ukichiro Nakaya, a Japanese physicist, was the first person to undergo a true systematic study of snow crystals, identifying and cataloging all the major types. In addition, he developed techniques to grow artificial snow crystals in the laboratory under controlled conditions, allowing him to determine the different environmental conditions that produced the various forms.

Snowflake is a general term that can refer to one ice crystal, a few crystals stuck together, or even the large clumps of crystals that sometimes fall when the temperature is around the freezing point. A snow crystal, however, is an individual object in which the water molecules inside are all lined up in a specific way and has a predictable shape. Sometimes raindrops freeze as they fall, but this is called sleet and doesn't have any of the elaborate patterns found in the snow crystals that form when water vapor transforms itself directly into ice in the clouds.

It is a characteristic of freezing water molecules that they stack together to form a regular crystalline lattice forming a prism made up of two hexagonal "basal" faces and six rectangular "prism" faces. This form occurs because certain surfaces of the crystal, the growth facets, grow at different rates. The hexagonal prism can be "plate-like" or "column-like", depending on which facet surfaces grow most quickly. By growing snow crystals in the laboratory under controlled conditions, scientists found that they grow into different forms depending on the temperature and humidity to which they are exposed. Shape depends mainly on temperature. The growth changes from plates around -2 C, to columns near -5 C, to plates again near -15 C, and to a combination of plates and columns around -30 C. The moisture in the air also plays a big part, as snow crystals tend to form simpler shapes at lower humidity and more complex shapes at higher humidity.

Snow crystal shapes depend upon a delicate combination of faceting and branching. The growth usually begins up in a cloud with a minute dust particle, which provides a structure onto which water molecules can start organizing themselves to form a crystal. When the crystal is very small, faceting dominates the growth, and the crystal quickly grows into a simple hexagonal prism. As the crystal grows larger, the corners of the hexagon stick out a bit further into the supersaturated air and thus grow a bit faster. The slightly faster growth at the corners soon causes the hexagon to sprout arms that all grow at about the same rate. Small bumps appear on the arms that stick out still further, allowing water molecules from greater distances to reach the bumps, causing them to grow even more quickly.

The developing crystal is blown about in the cloud and is subjected to its varying temperatures, and even a small change in conditions can lead to very different growth. Because each arm experiences the same environment, the arms tend to look alike, but since snow crystals all follow slightly different paths through the clouds, individual crystals all tend to look different. The longer a crystal remains in the cloud, the more intricate its shape.

This week's crystals have been large enough to see their complexity with the naked eye, but a hand lens reveals far more detail. It is easy to collect a few on a dark cloth but their beauty is so fleeting that they last only a moment or so before melting if brought into the warmth. Kenneth G. Libbrecht of Caltech, has a website he calls <SnowCrystals.com> which details his experiences and suggestions for catching these images with a digital camera. He says that, although the most challenging aspect of snowflake photography is that the crystals are so small, one can take some respectable pictures using a digital camera equipped with an adapter to which has been glued a 12x loupe (a small magnifying eye glass). He reports that the camera gives an image that looks pretty much like what your eye sees through the loupe, and the image scale is about right for snowflakes and should be relatively sharp. Give it a try.

December 6, 2005

It is an entirely different experience to walk a woodland path after a snowfall, as many of the common sights of previous days are completely hidden while other less-obvious objects are thrown into stark relief. I enjoy the widened vistas through the trees to the neighboring hills, the crunch of the snow beneath my feet, and the evidences of animals that had passed that way in their tracks. Less happily, I am also made very aware of the spreading patches of troublesome prickly ash trees throughout our woods.

We often bemoan alien trees that threaten native plants in our woodlands, but a far more serious problem here at the farm is this small native tree, a very enthusiastic plant that spreads by producing copious crops of seeds as well as numerous suckers that spring up from underground rhizomes. Prickly ash expands into extensive colonies and we have areas where hundreds of these small trees have formed impenetrable thickets. We attack by spending many hours during the fall and winter months, pulling, cutting, and treating any remaining stubs. They fight back by sprouting from any root bits left in the ground and by swiping their stiff thorny branches across any unprotected parts of our bodies and faces as we try to wrestle them onto a burn pile. It sometimes leaves us bloody but at least many of the trees "unboughed".

Despite its name, it is not an ash tree at all, although its leaves are similar and compound; that is, each leaf has a central stem with 5 to 11 oval leaflets with pointed tips extending out on both sides. Greenish-yellow flowers appear about April or May in dense clusters at the bases of last year's twigs, and it is interesting that male and female flowers grow on separate plants. The entire tree is protected with sharp spines or prickles and the bark, leaves, and fruits are highly aromatic. The dark red berry-like fruits that are born on the female plants grow in dense clusters and split open in the early fall to release single shiny black seeds.

When laboring in the woods trying to restrain the pesky tree, I try to remember that Native Americans prized it for its help in treating toothache. The twigs contain salicylic acid, a precursor of the chemical in aspirin and they chewed the yellow bark of the twigs to obtain relief. It was so widely used that it was often simply called "toothache tree." Internet search concerning this plant still brings up dozens of sites offering concoctions made from the bark as a stimulant for the central nervous system as well as treatment for rheumatism and circulatory problems.

I've never chewed the bark for a toothache, but I would never try to completely eradicate prickly ash, as it is the summer nursery for the giant swallowtail, our largest butterfly. It is closely related to citrus trees such as lemons and oranges, and female swallowtails that migrate up from southern states lay their eggs on it. The larvae are considered a pest in the citrus groves but we enjoy the butterflies and are happy to provide food for their young. I also read that the seeds are favorites of a number of birds, especially migrating flycatchers. Observers have reported their flocking to eat the oily seeds, even with plenty of insects available.

It pays to watch one's footing on the trails, so long as the ground is not frozen, as many newly raised tunnels criss-cross the paths. Some of our burrowing animals such as chipmunks and ground squirrels are probably sound asleep in their underground nests, but others continue to take advantage of the soft damp soil under the snow to extend their tunnel systems and some remain active all winter long.

Most of the blame for tunneling is usually placed on a mole, but the pocket gopher is also an efficient digging machine. This rat-sized rodent, named for the fur-lined storage pouches on each side of its mouth, uses both claws and teeth to dig, kicking away soil, rocks, and other debris from the digging area with the hind feet. It then turns a sort of somersault within the burrow, and uses its forefeet and chest to shove the dirt up to the surface. The gopher has four large, chisel-like front teeth, two on the top and two on the bottom, that are actually located outside the mouth so that the gopher can close its lips behind its teeth while digging to keep from swallowing unwanted dirt. These teeth can grow up to 14 inches in a year and must be continually worn down by chewing or they would grow right up through the top of the animal's mouth. Favorite foods are plant roots, bulbs, and tubers, and gophers are capable of doing considerable damage, as they eat approximately 60% of their body weight per day.

Voles also have been active as is evidenced by their much smaller tunnels than run about just under the snow surface. Owls and other predators have been known to thrust their outstretched talons down into these runways to snatch up one of the tiny animals that mistakenly thought itself safe, but usually the snow gives them adequate protection. There is much to see and experience in the winter woods, and although I must admit I sometimes have to push myself to get out and going, I'm always inspired and my spirit renewed when I do.