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

August 29, 2006

There are times when an excess of a particular animal, bird, or insect intrudes on our living space, causing us discomfort and distress. It may be deer or raccoons ravaging our sweet corn, woodchucks raiding our melons, an invasion of mosquitoes in our back yard, English sparrows and starlings nesting in the gutters, clouds of gnats about our faces as we hike, aphids on favorite plants, or Japanese beetles deflowering our roses. In every case, we demand relief, and often resort to electric fences, traps, sprays, nettings, and whatever else someone might suggest to rid ourselves of the problems. The plain truth is that we humans are only one part of the natural world and we have to adapt ourselves to it.

Population explosions are one major cause of conflict. Sometimes these occur because the balance of predator and prey has been disrupted, as in the case of the removal of wolves and other large hunters from an area allowing their natural prey to proliferate, or when a species has been introduced to new environs away from its native controls. Sometimes the vagaries of weather are at fault as when a plague of grasshoppers appears during a particularly dry period that allows more nymphs to mature, or when abundant rain provides unusual amounts of standing water for mosquito and gnat larvae development.

I had a call a week or so ago from a reader concerning the great numbers of Japanese beetles that are eating him and his neighbors out of house and home. As the name suggests, this beetle is native to Japan and was first found in the United States in 1916 in a nursery near Riverton, New Jersey. It is thought that the beetle larvae entered the United States in a shipment of iris bulbs prior to 1912 when inspections of commodities entering the country began. The Japanese beetle is about a half-inch long with a shiny copper-colored back and a green thorax and head. It is not a problem in Japan where it is controlled by natural enemies, but in America it has become a serious pest to rose bushes, grapes, and other plants.

Beetle traps are a favorite remedy and commercially available traps mimic the scent of virgin female beetles or a sweet-smelling food-type lure. This combination of ingredients can draw in thousands of beetles in a day, but research conducted at the University of Kentucky has shown that the traps attract many more beetles than are actually caught so that other susceptible plants in the vicinity of traps are likely to suffer much more damage than if no traps are used at all. They concluded that in most landscape situations, use of Japanese beetle traps probably does more harm than good. Hand collecting can better be used to protect valuable plants when these insects first appear. The presence of beetles on a plant attracts more beetles and when they are removed regularly, only about half as many are attracted to that plant compared to those on which beetles are allowed to accumulate. One of the easiest ways is to shake the insects into a bucket of soapy water early in the morning when temperatures are low and the beetles sluggish.

There are more than 300,000 described species of beetles. All have chewing mouthparts and well-developed antennae. They also have a pair of hard, opaque, waterproof outer wings, which usually meet in a straight line down the middle of the back which cover delicate flight wings, protecting them and the body from damage and drying out. During flight the forewings are raised and held out stiffly, allowing the hind wings to unfold and flap. Immature beetles include the white grubs commonly found under sod and feeding upon the grass roots, as well as predatory larvae such as those of ladybugs that feed upon aphids and other soft insects.

Beetles are found everywhere except in oceans and near the poles, and they occupy nearly every kind of habitat. Most are terrestrial, but some live underground and some live in water, and they range in length from under 132 in. to over 6 in. Some are brilliantly colored and others have a metallic or iridescent sheen. The majority are plant eaters, but there are also many predators and scavengers and a few parasites. Many are highly destructive pests of crops and gardens such as the Japanese beetle, but others are beneficial predators of harmful insects as the ladybug. The largest of the many beetle families is the scarab beetle family, with over 20,000 species, including the dung beetles that are invaluable scavengers. One favorite is the firefly or lightning bug that adds magic to summer nights. Both the adult and larval stages of the firefly are carnivorous and eat earthworms, snails, insects and even other fireflies.

Killing off the hoards of unwanted creatures is virtually impossible, and certainly flooding the environment with lethal chemical sprays or introducing additional species in an effort to control them is risky and often proves unwise. It seems that the best alternative for home gardens and ornamentals is probably a mechanical protection--hand picking, netting, or fencing (both electric and standard)--although perhaps the easiest and best solution, is to plant landscape materials that are not particularly attractive to the pests.

Even with the temperatures in the 80's and the sun burning down, it is hard to miss the signs that summer is winding down. The swallows are already gathering in large flocks in preparation for the journey south; some leaves on the sumac and walnut trees are turning color; the goldenrod is opening its first blossoms; the insect chorus is in full voice; and baby rattlesnakes have appeared at the big rock. Perhaps many of you are not overly fond of any snake, and some respond to my comments about our reptiles--particularly the rattlesnakes--with a shudder. Still, these creatures are an important part of the natural world, and learning about them may dispel some of the unfortunate myths that surround them.

A snake is an amazing creature. It has no legs, but can move around quickly because it has between 200 and 400 vertebrae in its back, each with a pair of ribs. (You have 33 vertebrae and 12 pairs of ribs.) The snake has no arms, but most can climb trees, and some can squeeze small animals so that they suffocate. A snake's entire skin is covered with scales, and each eye is protected with a transparent scale rather than an eyelid. The color patterns on its scales act as camouflage, usually allowing the reptile to lie quietly without detection.

All snakes are carnivorous, but because they are cold-blooded and don't have to constantly burn fuel to maintain body temperature, their food needs are a good deal lower than those of warm-blooded animals. A snake has specialized nerve endings all over its body to detect small changes in temperature and does best at 75-90 degrees F. It can stuff itself when food is plentiful and can shut down its body during lean periods, living off stored fat for up to a year. Its diet differs from species to species but usually includes earthworms, insects, eggs, frogs, birds. rodents and other snakes. To keep from freezing, a snake looks for a place to hibernate--perhaps a rock crevice, a tunnel made by a burrowing animal, or any protected site below the frost line. Generations of snakes return to the same hideout year after year, often one shared by several species.

A snake skull contains numerous small bones held together by elastic ligaments that allow the left and right sides of the jaws to move independently of each other. This may prevent a snake from chewing, but allows it to stretch to swallow much larger prey than it could otherwise manage. On the lower jaw there are small teeth that curve backwards, making it more difficult for captured prey to escape. The hollow fangs of a rattlesnake unfold from the roof of the snake's mouth, and venom is injected through the fangs that puncture the victim's skin.

Most snakes have cannot hear and have limited sight. The skull and jawbones pick up vibrations in the ground, allowing a snake to determine the size of a passing animal and its location. More importantly, however, a snake possesses two openings lined with chemosensory cells known as a Jacobson´s organ in the roof of its mouth. When it flicks out its forked tongue, it is collecting scent particles from the air and bringing them back into the mouth, where the fork tips are inserted into the organ. From there a signal is sent to the brain, giving the animal information about its surroundings. Pit vipers, including rattlesnakes, also have two pits under their nostrils to detect heat. These pits are so sensitive that the snake can determine the size of any nearby warm-blooded animal and can even locate one in complete darkness.

The timber rattler is a heavy-bodied snake with a broad triangular head, vertical eye pupils, and a thick black tail tipped with a tan rattle. Adults average 35 to 50 inches in total length and have dark cross bands extending along yellow, brown or rust-orange backs. Its average life span is about 20 years, with a maximum age of about 30 years. We discovered our first den shortly after acquiring the farm many years ago, but those snakes later moved to another site after the original became overgrown. This one is under a large flat rock on a west-facing hillside, and we visit it regularly to check on the pregnant females that spend the summer there.

Reproduction is slow, as a female requires at least seven years to become sexually mature and then mates only every third or fourth year. Consequently, some years there will be only one or two summering at the den, while at other times there may be half a dozen. A pregnant female does not eat, placing a great strain on her body such that she often has young only 3-5 times during her lifetime. In late August or early September, she gives birth to an average of 9 young, each of which emerges enclosed in a transparent membrane that the baby must tear open with its sharp egg tooth. The 10-inch long creature is equipped with a tiny rattle, venom and fangs, and has a velvety skin and coloring that is a grayed version of an adult's. The young snakes remain in the area a short time before shedding their skins and dispersing. Recent research has found that female timber rattlers can recognize their young, and they have been seen to provide some care and lay scent trails to help them locate winter hibernation dens.

It is reassuring to read that, during the past century, only one human fatality has resulted from timber rattlesnake venom across its entire range, and only two or three bites are reported each decade. We also read that less than half of all bites to humans by poisonous snakes even contain venom, as rattlesnakes can control the amounts injected when biting. We treat our rattlesnakes with considerable respect, but find them to be interesting and relatively docile neighbors.

The sunflower is a remarkable plant. Not only have botanists selectively altered our native annual species to give it a huge blossom, but it and most of the other sunflower types have some very special characteristics. We have both annual and perennial native sunflowers in Wisconsin but have only seen the perennial ones here at the farm. They have much smaller flowers than the domestic type but often grow to five or six feet in height.

What sets many sunflowers apart from other species is the ability to turn their heads. Each day, buds and immature blossoms follow the sun as it moves across the sky, facing toward the east in the morning and gradually turning westward as the day goes on. The actual movement occurs as a result of motor cells swelling or deflating in a flexible portion of the neck where the flower head is connected to the stem. Photoreceptors, which are specialized types of neurons, send signals to the motor cells causing potassium and calcium ions to be pumped into the tissues, as well as sufficient water to keep the concentration of chemicals constant. The head rotates because the motor cells on the shadowed side swell due to the fluid pressure rise. At night, the process reverses and the flower head will move back to its original orientation to face the sun in the morning. Presumably this system benefits the pollination of the flowers, as it ceases once the blossom matures and seeds begin to form. In fact, most plants you see will be facing east because they are mature, and because only the leaves of many of the perennial wild sunflowers seen on along the roadsides show any movement.

A sunflower head is actually made up of two types of the flowers, sterile yellow (or sometimes red or orange) ray flowers along the outer edge, and many concentric whorls of disk flowers in the central section. Each of these disk flowers is small and simple, and stands on its end packed tightly next to dozens of others. The reason for these spiral arrangements seems to be that it allows an optimal placing of the seeds so that no matter how large the seedhead, all the seeds can be the same size, with no crowding in the center or spaces at the edges. A perfect specimen will show superposed right and left handed spirals, and the seeds grow into the head of the sunflower along these spirals, each always equidistant from any other. This arrangement is also said to allow for the best use of the surface area, maximizing the number of seeds on the curved surface.

There is a fascinating phenomenon in nature that was explored back in the 12th century by an Italian mathematician, Leonardo Fibonacci. While he is also known for his work in bringing about the adoption of Arabic numerals, he made this interesting supposition. He imagined a pair of rabbits in a field under certain restrictions: they would never die, they would begin to reproduce at two years of age and they would produce another pair of offspring each year after that. The first year they would mate but not have young until the second year. The third year the first pair would produce another pair bringing the total pairs to 3. The fourth year both the first pairs would reproduce making 5 pairs and the following year three pairs would have young bringing the population to 8 pairs, and so on to infinity. This series of numbers, 1, 2, 3, 5, 8, 13, 21, 37, etc. where each number is the sum of the two numbers before it, is called the Fibonacci series, and is found in all sorts of natural situations.

Consider the head of a large sunflower. Its seeds are produced from the center out in a spiral fashion and a large head will have numerous spirals with smaller curves toward the center and flatter spirals the farther out it goes. The spirals appear to curve both to the left and to the right, and if you count the seeds forming them you will usually find that this pair of numbers is adjacent in the Fibonacci series. Typically, there are 34 spirals in one direction and 55 in the other; on a very large sunflower you may see 89 in one direction and 144 in the other. Count the petals on any flower and one often finds that the number is also one of the Fibonacci numbers. There is the one-petaled calla lily and the two-petaled spurge. Three petals on plants such as the trillium are more common and there are hundreds of species, both wild and cultivated, with five petals. Bloodroot and delphinium usually have eight petals and black-eyed Susans commonly have thirteen. The various daisies can be found with 13, 21, 34, 55 or 89 petals although any individual may not follow this general pattern.

It is not only blossoms that exhibit this tendency, but stems and leaves as well. The main trunk of a tree or stem or a smaller plant usually produces branch shoots that rest during their first two stages, and then produce a new branch bud at the beginning of each subsequent phase. Amazingly enough, if one counts these branches and the leaves that grow on them at each step of development, one often gets one of the Fibonacci numbers. Despite sometimes numerous exceptions, this is an orderly world.

August 8, 2006

You would think any sensible frog would give up looking for another mate at this time of year, but the gray treefrog was still calling hopefully on warm humid evenings just last week. This is the largest treefrog found in Wisconsin and its breeding season generally lasts from early April through July and even into August. It can reach two and one-half inches in length, and its loud trill is sometimes heard some distance from any water. It lives wherever it can find a small pond, a wet roadside ditch or even a stock tank, but is happiest near shallow water close to mixed stands of trees, shrubs and vines.

Despite its name, the gray treefrog is as often green as gray and has developed an intriguing color change system, allowing it to resemble whatever surface it rests upon. It accomplishes this by utilizing pigment-bearing cells within its skin that contain granules of black, green, orange, and yellow pigment scattered within them. Certain signals such as temperature, visual and nervous clues, and who knows what else cause some pigments to move and concentrate closer to the surface, changing the skin color and even its texture. If you turn one over, however, you will see that it has a splash of bright orange on its inner thighs, whatever its other hues.

Females reportedly choose their mates based on the duration of the male's call and will respond by touching her snout to his. Then the two will move to the water where the male will climb up on the female's back and grab her around the waist. Each female may produce up to 2000 eggs, and as she expels her eggs into the water, the male will eject a cloud of sperm that fertilizes them. After a period, which may be short or lengthy depending on the species and the weather, the envelope holding the egg in the mass will disintegrate and tadpoles will emerge.

A tadpole is the juvenile form of a frog, toad, or salamander. It breathes by means of external gills, lacks legs, and has a finlike tail that it uses to propel itself. As a tadpole matures, it gradually grows limbs and then (in the case of frogs and toads) absorbs its tail by controlled cell death. Most have small, specialized mouths to collect algae, but many are able to adapt to a carnivorous life style as well. When green food is plentiful, the intestinal tract is long and spiral for digesting cellulose, but if the amphibian population becomes too high, the food supply is depleted or drought drops the water level, some can adapt by feeding on other tadpoles living in the pond. Under these conditions, the gut shortens and alters to digest meat, and their development is speeded up. This cannibalistic behavior also results in deformed adults, as leg buds or other parts can be injured or destroyed. Industrial contaminants in the water have been routinely blamed for such deformities but some naturalists have contended that much of the damage can be simply due to overcrowding.

As the tadpole reaches maturity, its anatomy changes. Miniature hind legs begin to emerge, its digestive tract changes to prepare for its forthcoming insect diet, it develops forelegs, and finally the froglet resembles its parents. This transformation process can last anywhere from 12 days to 3 years, again depending on the particular species. The young frogs then leave the pond and in two years, they will be sexually mature.

Treefrogs have the remarkable ability to climb or rest on vertical surfaces. Some people have assumed that they have suction disks on their toes, but they are actually far more complex. The undersurfaces of the toe pads are made up of many wedge-shaped cells that are divided by deep crevices and which penetrate the cracks and irregularities of the surface to be climbed. Glands located between the cells supply a sticky mucous that also helps them hold on securely. Muscles surround the mucous pores, and presumably these muscles control the mucous so it's only released when tree frogs are climbing on slippery or vertical substrates. This characteristic is so impressive in the gray treefrog that if one is clinging to your finger, it can be quite difficult to disengage its toes.

A month or two ago, the shallow edges of our larger pond were black with tiny toad tadpoles, but now that these have matured and left the water, it is easier to recognize the remaining residents. Numerous insects and larvae move amid the seaweeds and lily leaves, but the biggest creatures are the red-tailed tadpoles of the gray treefrog. I have not noticed any limbs developing but it won't be long until a new crop of treefrogs will move out into the woods. Still, if the singing parents are any indication, other groups will be taking their places yet this year, and there will be plenty of treefrogs in the coming seasons.

August 1, 2006

The white mulberry tree that hangs over the road near the barn is a very popular spot these days, and will be until the last berry is gone. The tree is some 15 feet tall, but might have grown higher had not it sprouted in the shade of an oak. Still, it bears a bountiful crop of berries each summer and both animals and birds feast in its branches. The white mulberry is native to eastern and central China but became naturalized in Europe centuries ago, and then was introduced into America for silkworm culture in early colonial times. Silkworms will eat almost any of the dozen or so types of mulberry, but the species of choice is the white, perhaps because the leaves are smooth rather than hairy as are most of the others. However, the silk industry never took off in this country and was finally abandoned. In the meantime, the tree escaped cultivation, spreading across the Eastern part of the country, sometimes hybridizing with the native red mulberry.

There are three main species of mulberry in the United States: the red, the white, and the black. The black mulberry has the tastiest berries, but is found only in the southern states as it cannot survive our colder temperatures. It is native to western Asia and has been grown for its fruits in Europe since before Roman times. The red or American mulberry is native to eastern United States from Massachusetts to Kansas and down to the Gulf coast and is much hardier. Its fruits are usually deep red to almost black, and its leaves are "sandpapery" on top and hairy underneath. The white mulberry is so-named for the color of its buds rather than the color of its fruit, and is quite tolerant of drought, pollution and poor soil. Its berries are not as desirable as the other two and it is considered a weed tree in many parts of the country.

Some mulberries are either self-pollinating or either male or female, and sometimes will change from one sex to the other. The insignificant flowers are appear on short, green, catkins and are pollinated by the wind. Botanically, the crop is not a berry at all, but a cluster fruit somewhat like a blackberry, and ripens over an extended period of time.

Many of our birds relish the fruit once their brood-raising duties are completed. Robins, bluebirds, catbirds, orioles, tanagers, grosbeaks, towhees, cedar waxwings, and several of the woodpeckers are all known to feast on mulberries, and we have noticed several species spending considerable time in our tree. Especially welcome are the red-headed woodpeckers, as they never come to our feeders and they are relatively uncommon. An adult red-head is unmistakable, with a bright scarlet head, neck and throat, black tail, black wings with large white patches, and white underparts. They are birds of open woodlands, and require dead trees for use as nest sites, relatively open undergrowth, and access to the ground for foraging. They were once common throughout much of the Northeast but have declined in numbers, perhaps because of competition from European starlings for nest sites.

Unlike other woodpeckers, red-heads rarely excavate under tree bark to find insects, instead snatching flying insects from the air as do flycatchers, or dropping to the ground to feed on beetles and ants. They have even been known to enlarge the openings to get at the eggs or nestlings of hole-nesting birds. About half of their diet consists of vegetable matter, and their fondness for cultivated fruit and corn can make them a nuisance. They gather acorns and nuts in the fall, storing them in crevices and other cavities, and they often stay around during the winter if they have been able to stash away sufficient food to sustain them.

Catbirds are probably our tree's most common visitors. We seem to have a number of pairs nearby, as we see and hear them regularly. Their songs are easily recognizable as they use a variety of vocalizations and often include bits of songs mimicked from other birds. Catbirds rarely repeat phrases as do thrashers or mockingbirds and almost always include the catlike meow call that gives them their name. Nestlings are fed insect food almost exclusively until just before fledging, when fruit is introduced into their menu and the mulberries are handy and timely.

I often have spotted squirrels eating berries, and other animals always clean up what fruit falls to the ground. Then, last week I looked up into the bright beady eyes of a small raccoon cub that practically fell off its branch when it saw me below. A second baby was nearby and I rushed back to the house for my camera, catching the little bandits literally red-handed from berry juice. They may be nuisances in the garden but they are cute rascals and welcome to whatever wild fruit they can find.