October, 2005 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. .

October 25, 2005

I had a rare treat one morning last week. The grapevine had it that the current class of whooping crane youngsters was resting overnight nearby, and I drove out to see if I could catch a glimpse of them. It was a cool, absolutely calm dawn, favorable conditions for flying. There were thirty or so observers already on hand waiting for the show, well out of sight of the birds that were penned over a small hill, and five ultralights and a Cessna, ready and waiting for the patchy fog to dissipate.

The birds were the offspring of females from the captive flock, and had been sent to Necedah Wildlife Refuge while still in their eggs. Waterfowl chicks (as well as other babies that are hatched practically up and running) have a natural instinct to latch onto and follow the first objects they see. While still in their eggs, these had been pampered and serenaded with brood calls and, would you believe it, ultra light engine sounds, and when they hatched, a crane puppet head greeted them. The first few days they were kept warm under heat lamps and fed by costumed attendants, but as soon as they were strong enough to go outside, they were introduced to the ultralight aircraft. Again the recorded engine sounds and brood calls were used and the birds were taught to follow the plane around in the pen.

As the birds grew and developed their flight feathers, they were taken out to the runway where they exercised by following the handler and aircraft down its length. At length, when they were old enough, the ultralight lifted briefly into the air with the birds right behind. Each day with favorable weather, they flew for longer and longer periods, building up their strength and endurance and becoming used to following the plane as they would a parent.

The reason for all this effort is that if waterfowl are orphaned or raised in captivity and then released, they will not migrate, as most learn the migration route from their parents. The idea of training birds with an ultralight aircraft was conceived by William Lishman, a Canadian pilot who initially succeeded in leading a flock of a dozen Canada geese on flights around his home. Scientists from the Patuxent Wildlife Research Center and the International Crane Foundation envisioned this as a method of establishing an eastern migratory flock of endangered whooping cranes, and asked for a more extensive trial. Lishman and a friend then trained and led 18 Canada geese from Ontario to Virginia, and those birds returned on their own the following spring. Operation Migration was founded in 1994 and as proof of its success, more than 40 whooping cranes are now migrating in eastern North America, not counting this newest group.

These efforts are not without their excitements. As the fog burned off the runway and nearby field where the birds had been penned during the night, first one and then the others of the five ultralights took off, piloted by costumed handlers. Nineteen of the 20 birds followed the lead plane with the other slower crane trailing behind a second aircraft. The inexperienced birds tired quickly, and one plane after another would move in to entice straying birds to follow it, gradually coaxing them southward toward the next stopover some 50 miles away. Then panic set in as one bird became entangled in the supporting wires of an aircraft wing and the pilot had to land in a field with it hanging by one leg. Miraculously, it was not injured, and it was quickly captured by one of the supporting ground crews and sent on by truck to join the others who had already reached their goal for the day. The vagaries of Wisconsin weather then had their effects, and the cranes and their surrogate parents have been stranded at that site ever since, waiting another calm, clear morning.

Much has been learned about waterfowl migration, cranes, and the capabilities of ultralights from all of this, and perhaps other endangered species can be brought back from the brink of extinction by using this knowledge. The major accomplishment, however, has been the reintroduction of a magnificent bird into our state, and we give three cheers for the dedicated group of people who have brought this to fruition!

October 18, 2005

I've always had a soft spot in my heart for furry animals, and been willing to forgive them for a reasonable amount of damage to my garden. The woodchuck is a case in point. When we first bought the farm, Wilber was the first resident with whom we became acquainted. He lived under the barn floor and would sun himself daily in plain sight so that we even named him. He eventually proved that he was a "she" by producing a bunch of little woodchucks, and we were saved from an oversupply by Gus, our big male collie who took it as a personal challenge to rid the farmyard of any and all critters. Since Gus, our other collies also kept their numbers down, until Daisy came to live with us and couldn't hurt a fly. Now we have several in each of our many woodpiles, and we keep an electric fence around much of the garden.

Woodchucks are one of those species whose numbers have increased greatly since the arrival of European settlers. They were once relatively scarce in the forested eastern half of the country but as farms were established with their open fields and abundant crops, the woodchucks multiplied. Now they are a familiar sight to many people and there are even festivals in their honor each spring in many communities. The story goes that if the woodchuck, or groundhog as it is often called, emerges from his den on February 2 and sees his shadow, 6 more weeks of winter will follow. The legend was brought here by German immigrants from Europe, where it was the badger whose emergence warned of more winter to come.

The woodchuck is a rodent belonging to the group of large ground squirrels known as marmots, (most of which live in rocky and mountainous areas), and among North American rodents, only beavers and porcupines are larger. An adult usually grows to about two feet in length and has short, powerful legs for digging and a medium-long, bushy tail. An adult weighs an average of ten pounds, and consumes between 1-2 lbs. of grasses, leaves, fruits, and vegetables every day. It has large clawed toes on its front feet and typical rodent teeth; that is, 4 large continually-growing incisor teeth in the front for biting off vegetation and gnawing through roots which must be used constantly to keep them worn down, and eighteen chewing teeth which grind up the plant material.

Woodchucks are efficient diggers, and wildlife expert Richard Thomas has calculated that the average animal moves approximately 700 pounds of dirt when excavating a burrow. It digs separate summer and winter dens, often 5 feet deep to below the frost level and extending for 30 feet or more. The main entrance hole is about 8" wide, with dirt piled around it, and there are several other emergency exits that are less obvious. Digging is done so rapidly that a small burrow can be finished in one day, though upkeep is continued as long as the burrow is occupied. With their keen sight, hearing, and smell, woodchucks seem constantly on the alert and give a shrill warning whistle when alarmed. While preferring to flee from would-be predators, the woodchuck will vigorously defend its burrow when invaded by the occasional skunk, fox, weasel or domestic dog and can inflict quite a bit of damage with its teeth and claws, especially when the predator is at a disadvantage inside the burrow. When not hibernating or caring for young, woodchucks spend much of their time eating and sunning. They love to stretch out on warm ground, a smooth rock or along a low branch of a convenient tree although their tree climbing ability is limited.

The woodchuck retires to his winter den in late October, seals the sleeping chamber with dirt, and curls into a ball. It is a true hibernator as its heart rate slows down to about 4 beats per minute and its body temperature lowers to about 40 degrees. When the animal emerges in the spring, it generally still has enough fat left to sustain it, since several weeks may pass before there is sufficient fresh green plant material to eat. Woodchucks are being extensively researched because of these dramatic annual living cycles. It is thought that these are driven by hormonal signals, caused by seasonal changes in the hours of daylight. The innate cycles of the woodchuck are so strong that even in the laboratory, where the temperature is maintained at 70 degrees year-round with ample food and water, some woodchucks still stop eating and hibernate. It is interesting that their urge to hibernate is directly related to shorter day lengths but this seems to last only a limited time and then the processes are reversed, and the rodents emerge from hibernation ready to go. Better understanding of these cyclical rhythms might be very significant for human medicine as it is thought that we may experience similar cycles affected by photoperiod, although exposure to artificial lighting likely confuses the results.

The woodchuck provides dens for skunks, foxes, weasels, opossums and rabbits, and so occupies an important niche in the wildlife community. Also, because tremendous quantities of subsoil are moved in the course of burrow construction, the countless generations of woodchucks have contributed much to the aeration and mixing of the soil. Many farmers and gardeners consider them to be nuisance animals, however, because of their raids on garden and agricultural crops, as well as the piles of earth that interfere with haymaking. Still, one of my favorite wildlife pictures shows one of our woodchucks sitting up under the apple tree, happily chomping on a half-eaten fruit.

October 11, 2005

Writers for horror films have often used natural creatures as inspiration to spice up their stories, sometimes enlarging them to monster size to enhance the effect. In the Star Trek II film, "The Wrath of Khan!" they use a large scale-model of a little doodlebug, and most viewers probably didn't realize that this remarkable insect really exists. Properly called an antlion, the tiny insect makes funnel-shaped, crater-like pits in soft dirt or sand, and then waits patiently at the bottom to ambush any hapless passer-by that happens to fall in.

Actually, it is only the antlion larva that is a predator. This is a ferocious-appearing creature that has an enormous pair of sickle-like jaws with several sharp, tooth-like projections that pierce the victim, injecting venom that dissolves the body contents, and then suck out its body fluids. It seeks out a dry, sunny spot sheltered from wind and rain that has sand or light soil that is easy to move. Pushing itself backward, the larva first inscribes a circle on the ground. Then, digging deeper and deeper, it spirals in toward the center, throwing the dirt out with its long jaws. Eventually the crater reaches 1 1/2 to 2 inches across and almost as deep, with very steep walls. The slope adapts to the critical angle of repose for sand, so that the sides readily give way under the feet of the victim, carrying it down into the open jaws of the digger. In the process of making their pits, antlion larvae create spiral-shaped marks looking as if someone had been doodling in the sand, giving them the nickname "doodlebug". When a crawling insect, such as an ant, inadvertently falls into the pit, it is virtually impossible for it to scale the loose sand on the steep walls. To make matters worse, the antlion quickly flips out more sand, thus deepening the pit and causing miniature landslides that knock the struggling ant to the bottom. In contrast to the movie and fortunately for us and other mammals, this larva grows only to _ inch in length.

When it is fully grown, the larva moves deeper into the sand to construct a cocoon. It extends its heavy abdomen and extrudes white silken threads that glue the sand grains into a hollow sphere around it. When the cocoon is completed, the larva transforms into a pupa where it remains for several weeks or over the winter. When the pupa hatches, the transformed insect breaks through the wall of the sand cocoon and pushes itself up to the surface. It climbs up onto a nearby branch or twig and hangs, expanding and drying its wings, and soon flutters away in search of a mate. At this point, it is about 1 _ in. long with a wingspan of about 3 in. and looks much like a damselfly, with two pairs of long, narrow, many-veined wings and a long, slender abdomen. It can be easily distinguished from this other delicate insect, however, because it flies only at night and has longer, clubbed antennae. An adult antlion may eat small flies or drink water, but its real purpose now is reproduction, and it lives only long enough to mate and lay eggs.

We usually see antlion pits in the dry sand at the bases of the sandstone cliffs that border our hilltops and in the sawdust piles around the sawmill, but other observant people may discover them in the sandy soil of their flowerbeds, under hedges or eaves, and under buildings set on piers. I was surprised to read that many people find them fascinating "pets", and keep them in sand-filled bowls or aquaria, feeding them ants. I suppose it would not be too different from raising caterpillars and watching them change into butterflies or moths, but I would much rather provide green leaves for a pet rather than other live creatures.

I try not to miss my daily walk in the woods, as the first gun deer season will soon be upon us and the presence of human hunters will keep me off the trails and restricted to the roads. Other creatures hungry for blood are already present in large numbers, however, as suddenly the ticks seem to have realized that time is short and they better find a host. I don't think I have picked up any so far, but husband Bill found one crawling up his arm and Daisy must have collected a dozen or more this week. They typically climb to the tips of grass blades, plant stems or branch tips and wait with front legs extended to grab rides on a passing meal. Once aboard, the tick inserts its spear-like mouthparts into the victim, injects an anticoagulant, and remains several days ingesting its blood. Contrary to popular belief, a tick does not bury its entire head under the skin but once the "spear" is imbedded it can be quite difficult to remove until feeding is completed. The major problem lies with any disease organisms that the tick might transmit, although if it is removed within 24 hours, there is little danger of any harm except for an itchy welt.

Keep your eyes on the skies in the next few days as this year's whooping crane class will be passing through our area as they head south behind their "mother" ultra-light. The twenty chicks have been flying more-or-less together for the past couple of weeks and are scheduled to leave Necedah Wildlife Refuge on October 10th, weather permitting. That would be quite a sight!

October 4, 2005

With the terrible costs to human life and livelihoods in the wake of the recent hurricanes, it seems almost unfeeling to think about their effects on the wildlife but I worry about our migrating birds. Many of those that kept us company all summer, building their nests and raising their broods, were undoubtedly traveling somewhere along the paths of those two giant storms, and some had probably arrived along the coastline. Migration is a dangerous process, and it is sometimes difficult to believe that the perils out-weigh the benefits, although scientists contend that if it had not been beneficial, the behavior would not have evolved. Migrant species probably experience less competition for space and food for themselves and their offspring by traveling to northern areas where there are fewer permanent residents, and then by returning to milder climate for the winter to avoid the problems of cold and snow. Still, untold numbers of migrants die each year from storms and attacks by predators.

We watched a flock of migrating white-throated sparrows being harassed by resident birds, even the tiny hummingbirds, and no doubt wherever they travel, locals birds object to their arrival, driving them away from food sources. Even worse, the larger predatory birds take advantage of their vulnerability in strange surroundings to prey upon them. Lighthouses, buildings, and TV towers have been responsible for many avian deaths, as brightly lit structures seem to have a dazzling effect that not only lures but confuses them, particularly in fog. Of all the hazards, however, strong winds and storms can be most lethal, particularly while crossing large bodies of water.

It was Aristotle and his students who evidently were the source of the old belief that birds hibernated, contending that the disappearance of many species of birds in the fall could best be explained by their hiding in hollow trees, or in the mud of marshes in a torpid state, as do many other creatures. Other early writers tell of flocks of swallows seen congregating in marshes where they submerged themselves for the winter, and of fishermen in northern waters who pulled in nets to find hibernating swallows mixed in with the fish. This idea was finally discounted, but it is true that chickadees, swallows, hummingbirds, and swifts regularly do go into torpor under cold stress, so there was some basis for their theories. Aristotle also was the originator of the idea of transmutation, the seasonal change of one species into another. Observing that one species would appear just as another species departed led him to reason that the two different species were actually one, simply acquiring different plumages at the change of the season.

It is no wonder early observers came up with fantastic theories, for the reality of bird migration is almost as unbelievable. Four-gram hummingbirds travel 350 miles non-stop across the Gulf of Mexico, and warblers, almost as tiny, make even more extended flights. Many used to insist that these birds must be catching rides on larger birds but this has also been discounted.

Both length and duration of migratory journeys vary greatly between families, species, or populations within a species. Our cardinals, chickadees, titmice, and most woodpeckers may live out their entire existence within 10 miles from the nest where they were hatched. Some sparrows, meadowlarks, and blue jays make such short migrations that it is hard to tell if the birds you see are those that nested here or individuals from farther north. The robin has populations that nest from Canada and Alaska to the gulf coast, and most of the more northern birds move at least some distance south for the winter, completely mixing up the various groups. Some red-winged blackbirds nest in the southern states, but in winter they are joined by other subspecies that nest as far north as the Canada. In certain populations of song sparrows, males remain all year on their northern breeding grounds while the females and young migrate south. In dark-eyed juncos, adult females migrate the farthest south, while young males winter the farthest north, and adult male and young females winter at intermediate distances. One group of palm warblers makes a 3,000-mile journey from Great Slave Lake to Central America early in October while another segment of the same species, that nests farther south, stops at the gulf for the winter.

More than 300 breeding species leave the United States and Canada and spend the winter in the West Indies, Central America, or South America. Some nighthawks, swallows, and thrushes may in migrate to Argentina, 7,000 miles away, while Arctic Terns travel 11,000 miles. It is also interesting to note that although northern birds often migrate to the southern hemisphere, no southern hemisphere birds come up here.

Night travel is probably the best for the majority of birds because by moving at night, they can devote the daylight hours to feeding and resting. Radar has provided some of our best information of ground speeds for migrating flocks. Ducks and geese have been observed to fly at a rate of 40 to 50 miles per hour, songbirds around 30 miles per hour, and herons and hawks were found to move at 25 miles per hour. In the spring, all the birds travel faster when hurrying toward the breeding grounds while in the fall, the flights are more leisurely, so that after a few hours of flying, birds often pause to feed and rest for one or several days. Drive slowly down back roads these fall days, for the birds that fly up in front of your car may be on long journeys and we want them to arrive safely.