November 28, 2005

Most hunters we know enjoy the meat of any deer they bag, but it is taking an animal with a rack of large antlers that causes them to brag. What is it about these strange projections that makes them so prized? Most large grazing animals have either horns or antlers that are used for defense and in duels between males for possession of a female. Although both have a similar purpose, they are very different structures. Most cattle, sheep and goats have horns. These are hollow horny sheaths made of keratin, the same substance as our fingernails and enclose pointed bony cores that arise from the front of the skull. Horns are unbranched, are never shed, are commonly found on both sexes, and continue to grow throughout the life of the animal.

Antlers, on the other hand, are usually found only on male deer and are the fastest growing tissue known. They begin to develop in early spring, starting as soft, swollen pads on the skull and lengthening into club-like structures. Antlers are live tissue, composed of bone and growing at an average of 1 to 2 inches per week. During this time, they are covered with a soft brown-haired skin called "velvet" that protects the many tiny blood vessels that carry food and minerals to the growing tissues. Antlers in velvet are delicate and easily bruised and will bleed if scraped against a tree or branch.

Its first fall, a young buck will grow small bumps, called buttons, and by the second fall, it will usually have one or two points on each small antler. At 2 1/2 years, a buck will usually have 3 to 5 points on a side, and a mature animal will usually grow medium to large antlers with additional points. A popular belief is that you can tell a deer's age by the number of points on each antler, but the only true way to tell a its age is by its teeth, as the size and shape of the antlers is greatly influenced by genetics and diet.

During the summer when a buck's antlers are growing, they act as air conditioners to help get rid of extra body heat. Then, after three or four months, the blood supply is cut off and the antlers harden. The dead and dry velvet peels off in strips, helped along by vigorous rubbing against trees and other sturdy uprights. During mating or rutting season, a buck uses his antlers to fight other males, lunging at any intruding stranger head on and sometimes even locking antlers. After a few minutes of shoving and pushing, during which pieces of antler may be broken, the weaker male will usually retreat, leaving any nearby females to the victor. After the breeding season in January or February, bucks will shed their antlers, the growths separating easily from the skull bone and leaving smooth scars with no jagged edges. The discarded antlers are a welcome treat for mice, chipmunks, squirrels, and porcupines because they contain calcium, salt, and other minerals.

Prehistoric man used horns and antlers as tools, but they were also utilized in medical treatments in the Orient. The first written reference dates back to a scroll from the Chinese Hun Dynasty, 206 B.C. to 200 A.D., in which deer antler velvet was recommended for 52 different diseases. Chinese medical books claimed that the substance helped the kidneys, improved lung function, increased vitality, improved circulation, and sharpened mental awareness, among other things.

The term velvet originally referred to the fine hairs on the antler, but is now used specifically to indicate its immature stage before it calcifies. It has a cartilage-like texture and has a velvety feel. Velvet antler calcifies from the bottom up to the top and it must be harvested at the right stage, usually from a living animal that is not harmed by the operation. It is then dried and sliced or powdered. The most common use is for relief of rheumatism and arthritis, but it is also used for a variety of other purposes, ranging from sexual disorders to enhancing athletic prowess. Ossified antlers that fall off naturally are still valued but must be boiled to yield a gelatin that can be used for certain applications, such as easing swelling.

Today, there are some 35,000 deer farms in Korea, New Zealand, China, Russia, Mongolia, and, more recently, the United States. They produce animal meat to be used as food, and antlers that are usually exported to the Orient, though antler-based health products are now manufactured for domestic consumption around the world. Traditionally, deer antler is sliced very thinly or ground to powder. The thin slices are made by removing the outer, hairy portion of the antler, soaking the antler in hot alcohol to soften it, and then carefully slicing it to produce round wafers. The slices are best suited for soaking in wine to make a "tincture" of antler. Very thin slices can be eaten directly. To make gelatin, ossified antlers are boiled for several hours to release the gelatin that also can be dried and ground into powder, and consumed directly. According to one internet source, the old deer horns have become the latest aphrodisiac craze in California. Only the tips of the horns are used and make a powder that is then pressed into pills. While there is no scientific evidence regarding any supposed benefits, it doesn't bother the deer as they have already discarded the antlers, and its use is both legal and safe. I think I'll leave any antlers I find for the mice, however.

November 22, 2005

When I was a child, many households kept a canary in the living room to enjoy its cheery song. My Ohio grandmother raised the birds for a number of years, so we had a ready source, and our home always had a bird or two. It was usually my job to care for it, feeding and cleaning its cage, and the birds became quite tame, sitting on my finger or shoulders and flying about the room. As I grew older and saw my first native goldfinch, I was struck by the similarities between the two birds, so much so that I just assumed that one was a domesticated version of the other. I have since learned that although goldfinches are often called wild canaries, they are not the same species.

Goldfinches are birds of the open places and except when nesting they are usually seen in roaming about in flocks. In spring they eat the seeds of last year's weeds, the tender buds of trees and shrubs, and many small insects. In summer and fall, they feed mostly on seeds of dandelions, thistles, asters, goldenrod and sunflowers. Goldfinches are between 4 1/2 to 5 1/2 inches long and weigh about a _-ounce. During the summer months, the male goldfinch is bright lemon yellow with a black forehead, wings and tail, and has a sweet song. The female and young are less showy as they lack the black caps and have olive plumage, although they do have black wings with whitish bars. Males lose their black caps during the winter, as well as much of their yellow coloring, so that many people do not recognize them and assume the birds have left the area.

Of all our birds, except for those that raise a second brood, the goldfinch is the last to nest and raise a family. Very few nests are started before July, and most containing eggs or young are found during August. The compact cup-shaped nest is constructed of milkweeds fibers and fine grasses or weeds, and usually lined with thistledown. They frequently build in the crotches of tall sturdy weeds such as the bull thistle, Joe Pye weed, wild lettuce and even goldenrod, but will also nest in shrubs and small trees. The female usually lays four to six bluish white eggs and is fed by the male who spits up partially digested seeds from his crop. The nestlings are fed by both parents in the same manner, and it seems likely that the abundance of suitable seeds in July and August is responsible for the late nesting habit. In autumn, many goldfinches head south, where they move around in large flocks searching out areas with abundant food, while others hang around, perhaps because of the numbers of feeders now present in the northern states. We have them all winter in considerable numbers, and enjoy watching their typical undulating flight and hearing their high twitters as they come and go.

It is believed that all the present breeds and varieties of canary, despite their variations in color, shape and song, are descended from a single, drab green ancestor with grey and brown streaking on its back, native to the Canary Islands off the coast of Africa. Interestingly, the Romans named the these Islands after an extremely large type of dog that was bred by its inhabitants. ("Canary" is a corruption of "canis", Latin for dog.) The invaders had no interest in the birds, but others noticed their sweet songs and began domesticating them early on, simply calling them Canary birds. They were first brought to Europe in the fifteenth century where they became the prize possessions of royalty, who treasured them for their almost constant singing. Over the centuries, though, canaries were selectively bred for other characteristics such unusual color, creating not only yellow birds, but also white, or mixtures with black, green, and orange.

Canaries were traditionally used in coalmines for detecting trouble, as they are extremely sensitive to toxic gases. Anything that affected the birds was immediately noticed because canaries otherwise tended to sing most of the time and their silence became a warning. The use of canaries in British mines was not phased out until 1986.

Canary breeding is a popular hobby and the birds are judged in competitions every fall and winter. The world show is held in Europe each year and attracts thousands of breeders and as many as 20,000 birds. Canaries are generally divided into three main groups: those bred for their many colors; type canaries bred for their shape and conformation; and song canaries bred for their unique songs. Many British and European enthusiasts have concentrated on the size and form of the bird, producing types with strange shapes or plumage such as the scantily feathered Italian Gibber Italicus and the frilled canaries whose feathers are long and twisted. The American Singer is very popular in this country and is the result of many crosses between various types of song canaries. This breed, as well as some others, is capable of a certain amount of mimicry, and it is possible to teach them simple instrument tones, some wild birdcalls, and even a word or two of human speech.

At this point in my life, I much prefer to see birds wild and free rather than caged, but must admit that the sound of a singing canary brings back childhood memories. And one day, when I can no longer get out to hear the goldfinches, I might again acquire a canary to sing for me. (Serinus Canaria by E.F. Bailey 1907

November 15, 2005

George has taken up his stand in our front yard again, dutifully offering sunflower seeds to any takers. For any new readers who are not acquainted with him, I should explain that he is put together from a steel fencepost with a cross bar attached and a gallon plastic milk jug inverted on its top for a head. He is dressed in an old jacket and straw hat, and has a shallow basket hanging from one arm. After the birds become accustomed to his presence, they come and go freely, and when I borrow his hat and basket, they accept me, as well. This process usually takes a week or so, but this time I couldn't resist donning his hat to see who would come the first day. Almost immediately, a male goldfinch landed on the rim of my basket no more than a foot from my face, and it was a real treat to be able to examine a small living bird so closely. Chickadees, titmice, and a female house finch soon followed, and I resolved to spend at least a few minutes there every day. Before long they will be eating from my hand, and I look forward to that experience all year long.

This close encounter brought to mind the controversy about bird feeding that erupted in December 2002, as the result of a front-page article in the Wall Street Journal by James Sterba. His rather lengthy column questioned the advisability and safety of attracting birds to central feeding stations, and I would bet that had he known about the supposedly imminent danger of a world-wide pandemic of bird flu, he would have stuck that in, as well. It is true that such a treatise might better have been put on the editorial page with a disclaimer that it was his opinion rather than as a news item, but I felt that he did have points worth considering.

First, he contended that putting out an inviting food supply draws a large number of birds into a small area, setting up conditions for the feeders and the ground beneath to become contaminated and any disease to spread. Also, infrequent maintenance and sanitation can mean moldy seeds, possibly resulting in illness. He does get in trouble for citing the decline in numbers of house finches as proof of these dangers. He states that they have dropped by 60% in the past decade in the eastern U.S., apparently because of conjunctivitis-a highly contagious eye disease. However, he neglects to mention that this very well might be a natural correction for the population explosion of this species in the past 60 years in the eastern U.S., and that their numbers have stabilized now.

He is also correct in stating that feeders draw birds into the range of free roaming house cats. It is important to place feed away from any ground cover in which cats and other predators can hide, and to provide plenty of safe high perching sites nearby. Cats are efficient, genetically programmed hunters, and I am always skeptical of owners who contend that their well-fed pets don't kill birds.

We have also seen an occasional hawk snatch a bird at our feeders, but the population of these predators has not been artificially increased as has that of cats. Any action that alters the natural balance is bound to have its effects, however, and this is undoubtedly true with bird feeding.

There may be some truth to Sterba's anti-feeder arguments, but we can minimize the negatives with a little thought and regular maintenance. A poorly maintained feeder probably does serve as a repository for avian diseases, so it's the birdwatcher's job to keep the feeder clean; after all, you wouldn't let the food in your dog's bowl get moldy, so the same should go for your bird feeders. It's also advisable to feed in an area where there are nearby evergreen trees, or other thick branches into which birds can escape from predators. Installing plants that bear fruit or provide nesting material will also benefit the birds as well as the bird-watcher.

We know of no scientifically rigorous studies that have shown that feeding birds is bad for them, but there's also no conclusive evidence that it's particularly good for them, either. Some birds have extended their ranges in recent years, but it is difficult to prove that feeders were the actual cause. In the long run, it may be that feeding birds has little impact on wild bird populations, but I suspect that our help will be increasingly important for some species, especially as we continue to destroy natural habitats in which birds historically found food and shelter. In any case, feeding birds is an educational, rewarding pastime for millions of people, and sometimes the only close contact some have with the natural world around them. I certainly plan to continue feeding, but I do resolve to do a better job with sanitation, and watching out for the safety of my avian visitors.

November 8, 2005

We are not the only creatures enjoying these relatively balmy days, even while the calendar tries to tell us it is well into November. It is true that we have experienced some frosty nights, but there are still calendulas and violas in bloom in the garden and the crickets and grasshoppers continue to serenade us during the warmer periods. One of these days, an arctic blast will bring their songs to an end, but they have long since laid their eggs, ensuring a new generation will replace them next summer.

Grasshoppers and crickets belong to two different families, but they are alike in a number of ways: both feed on plant material; both usually have two sets of wings, one that is thicker and tough and covers the second more delicate set that folds up underneath; they both have strong rear legs that are used for jumping; and their songs are usually not heard until the last weeks of summer or early fall months. There are also a number of differences: grasshoppers are usually out and about during daylight hours, while crickets hide under a rock or other protection until nightfall; grasshoppers feed upon living leaves, while crickets are mostly scavengers, feeding on decaying plant material, fungi, and seedling plants; adult crickets rarely measure over an inch or two in length, while most grasshoppers grow to double that size and some species can reach five inches; and grasshoppers are brown with a herringbone pattern on the upper section of their hind legs, while crickets are usually completely black.

The life cycles of these insects begin in the late spring, when the eggs that were laid the previous year hatch. Grasshoppers come in two general types, long- and short-horned, the term referring to the length of their antennae. The long-horned species include katydids and a variety of other insects whose antennae arch over and often extend beyond their bodies, while our common garden grasshopper is a short-horned variety. The newly hatched larva of a short-horned looks like a tiny worm and works its way to the soil surface where it quickly molts to become a hopper. It grows on a steady diet of leaves until its skin can stretch no tighter. At that point, it will rest a few days to develop a new loose skin under its existing one and then swallows air to build up pressure to split the old one. This will occur five or six times as the insect grows, with each molt revealing a nymph that looks more and more like an adult. In the final stage, the grasshopper is equipped with wings, and even then, it will continue to grow for some time before becoming sexually mature.

Short-horned grasshoppers have adapted to a great range of habitats but their development may be suspended in any stage for weeks or months under unfavorable conditions. In some species a prolonged shortage in the food supply can cause the next generation to undergo a change that produces migrating adults, often called locusts. These may travel hundreds of miles in a few days, and have been sighted by radar flying at altitudes up to three thousand feet in enormous numbers. These swarming locusts are greatly feared, but actually the damage done to crops by the less conspicuous common grasshoppers is usually much greater in the long run. The development of crickets is similar to that of the grasshopper, but often requires ten molts to the grasshopper's five to reach maturity.

The grasshopper has a selection of a dozen different sound variations that are created by rubbing its hind legs across the wings folded along its body. On the inside of the leg is a row of tooth-like projections that make the wing vibrate as the leg is moved over it. Different species have different arrangements of teeth or move their legs at different speeds, and it is the pattern created by the varying intensity of these vibrations that makes the sound unique for each species. In grasshoppers, sound signals are very important, especially during courtship. In the breeding season, all males produce one type of sound, competing with each other to attract females. As a female approaches a particular male, he immediately switches to his courtship variation and while mating he has a conquest version.

Each male cricket advertises his presence and prowess by scratching together the bases of his forewings, which are ridged like tiny washboards. Each stroke creates a single chirp, and the cricket's song consists of a trill composed of a series of chirps. Like the communications of many males, the trill carries two meanings, an invitation for females and the opposite for other males. Researchers at Cambridge University in England have found that when a cricket begins to chirp, the nerves that transmit the sound to its brain are temporarily deactivated to keep it from being deafened by its own song. The male is genetically programmed to produce his own species-specific song, and the resulting chirping sound is picked up by the female's ears on her front legs that she matches to an internal model of what her particular species should sound like.

Grasshoppers are almost universally reviled, but house crickets have often been associated with good luck, and in the orient, they have been kept in small cages of bamboo and valued for their song. In my childhood home we always had them singing in the downstairs woodpile and I miss their cheerful chirps in our more modern basement.

My greenhouse plants are back in their winter quarters, snug and warm despite this week's frosty nights. Everything that was movable has spent the last six months out-of-doors, and the tropicals thrive in the sunlight and open air. Many also become hosts to a variety of creatures that come in with them, most of which are not welcome, and I usually have to go over their stems and leaves, removing scale, aphids, and other creepy crawlies. I also have a major problem with box elder beetles that see this warm sunny building as a great winter resort, and collect by the hundreds on the plants and walls. The Asian ladybugs are also a nuisance but they are less bothersome as they earn their keep eating the bad invaders.

Among my plants brought in from the garden are potted tomatoes that spent the summer on a porch in town, and it was soon evident that they also had baggage. The top of one became completely leafless and there was evidence of other chewing on several other branches. It took careful examination to find the pale green tobacco hornworms that were doing the damage, but, unlike the other critters that were making themselves at home in the greenhouse, I was pleased to see them. I must admit that most gardeners are probably reacting with an "ick", and would be happy to squash these potentially large caterpillars that may reach four inches in length, but I have always had plenty of tomato plants and am happy to share with them. The problem has been that, for some reason, they don't seem to come to my garden, and I have almost never seen one here.

Tobacco hornworms as well as the very similar tomato species are the larvae of our largest hawk moths. These insects may have wingspans of up to five inches and although they are a rather non-descript mottled gray, they do have bright yellow spots down the sides of their abdomens. These become quite visible when the wings are extended but are covered up when the moth is at rest and hiding. Many people mistake them for hummingbirds when they see them hovering in front of their garden flowers, but the moths feed at dusk when hummingbirds have retired for the night.

The adult moth lays eggs singly on the underside of leaves of tobacco, eggplant, potato, pepper, or related weeds. Larvae are pale green with white and black markings and develop eight white, lateral "V-shaped" marks. A projection or "horn" on the last abdominal segment (red for the tobacco species, black for the tomato type) gives the caterpillar its name. Though initially quite small with a body about the same size as its horn, the caterpillar will pass through four or five larval stages to reach full size in about a month.

Caterpillars are rather unique as the newly hatched larva has the same number of cells as the large caterpillar that is ready to pupate. As they grow, their "skin", which is actually an exoskeleton, becomes too tight on them, and a molting hormone stimulates them to grow a new one beneath the old. The original then splits down the center, revealing a new soft exoskeleton. Before it can harden, the caterpillar swallows air to expand its body and allow room for growth and eats on. Caterpillars are very limited in their diet and many species will only eat the leaves of a single type of plant. Most of a caterpillar's body is filled with intestines that quickly digest its food since the caterpillar must store enough food energy to carry it into the adult stage, and sometimes for its lifetime.

Caterpillars have two types of legs, three pairs of jointed legs with hooks that hold onto its food, and additional paired prolegs used for walking and grasping. These are short and stubby and equipped with microscopic hooks that act very much like Velcro. They look like tiny black combs and are very efficient at grasping leaves or stems, making it very difficult to remove a caterpillar from its host. A caterpillar moves in a rippling fashion, contracting the muscles in its rear segments that pushes blood forward and lengthens the front part of the body. The legs hold onto the forward position and then the front muscles contract, pulling the rear segment forward. During metamorphosis the prolegs disappear and the moth emerges bearing only the six true legs.

Besides its own cells, a caterpillar has sacs called imaginal discs that contain clusters of cells that will develop into the structures of the adult insect, such as legs, wings, and antennae. These multiply inside the caterpillar but don't become dominant until the fully-grown larva drops off its plant and burrows into the soil to pupate. The hornworm pupa is rather distinctive in having the developing mouthparts in a curved-down projection on the front. During the summer months, moths can emerge from pupae in about 2 weeks, but those growing later in the fall remain underground all winter.

I have never been successful in growing hornworms through their complete cycle, and am hoping for better luck this time. I salvaged a number of tomato stems before frost and transferred the caterpillars to them to save my potted plants, and I'm hoping to carry them through the winter to start a population in my own garden.