March 28, 2006

We did some spring-cleaning this past week-not in the house that I must admit could use it, but in the wildflower garden across the road. Burning last year's debris makes room for the new growth that will be springing up in the coming weeks, as well as returning nutrients to the soil. While our other prairie remnants get the treatment less frequently, the demonstration plot is burned every year, preparing it for the many visitors who come during our annual openhouse weekends held at the end of April and beginning of May. The bared, blackened ground heats up quickly under the strengthening rays of the sun, and the plants respond by pushing up with enthusiasm.

We never burn the woodland sections, for not only do those plants and the small creatures that live among them need the humus and thick layer of dried leaves that would be destroyed by such action, but hepatica and spring beauties have already developed buds that we wouldn't want to scorch. Both will open their first blossoms in the next week or so, as soon as we have a few warmer days and nights.

Hepatica is a member of the buttercup family, and well-grown plants have multiple crowns just at the surface of the ground that grow from starchy tubers that can be up to an inch in diameter. Last year's old and weathered leaves mark their locations and already clusters of fuzzy buds are showing which will soon open into one-inch pink, lavender or white blossoms that will last several weeks before fading. Interestingly enough, these blossoms have no petals, but instead present showy bracts surrounding a large number of delicate sepals, which in turn frame dainty yellow stamens.

As the flowers fade, more hairy tuffs emerge that are the new leaves. These are dark green with three lobes, and tend to be leathery above and covered with dense hairs on the undersides. Soon, oblong, sharp-pointed fruit will appear which can grow up to 2" long and reportedly are popular with the chipmunks. No doubt other rodents and insects feast on them as well, but plenty of seed survive, as is evidenced by the number of new plants we find each year. In autumn, the leaves turn shades of russet and purple, persisting through winter and continuing to provide some nourishment to the plant.

Not too long ago hepatica was viewed as a cure-all for many ailments. The Greeks named the plant 'heper', meaning liver (after the shape of its leaf). It was believed that a plant would be good for ailments of a look-a-like organ and references to the hepatica are found in documents as early as the 1500's. There were no raves about its efficacy, however, until an enterprising druggist touted it and created a huge demand for the plant. It was the prime ingredient in "Dr. Roder's Liverwort and Tar Sirup", and in 1883, over 450,000 pounds of dried leaves were harvested for export or domestic use in a single year. This represented an enormous number of plants considering their small size, but luckily the craze soon fizzled.

The spring beauty belongs to the purslane family and grows from a small tuber something like a potato; if fact, one of its common names is fairy spuds. The flowers are composed of five whitish petals, striped inside with dark pink, and one must get down close to appreciate their delicate beauty. Although individual flowers are only a half-inch across, their massed display can be spectacular. They are born in loose racemes above a pair of opposite, narrow leaves that grow out midway up the stem. Spring beauties seldom stretch up more than three or four inches, but often spread into large colonies on favorable sites. Each stem has a succession of buds that allows for a long blooming period sometimes lasting into June. The variety we have here has leaves that are almost grass-like, while another type found farther north has more oval foliage. The tubers, as well as those of the hepatica, supposedly have a sweet chestnut-like flavor, but I have never sacrificed a plant to taste one. Native Americans and early settlers did, however, and as the plants often grew in large patches, they were undoubtedly a welcome addition to a sparse diet. The blossoms give way to small capsules containing seeds that self-sow readily when the site is to their liking. Within a few weeks the above-ground parts die down, leaving the underground tuber with its stored food to lie dormant in the soil until the next spring.

We didn't see the whooping cranes that stopped over at the river last week (although more will likely be coming), but there is no missing the bluebirds that are singing loudly, vying with the robins, cardinals, and redwings. Even cold mornings are no longer quiet as they were a couple of weeks ago, and when the sun rises over the hill, it is greeted by a chorus of singers. Springtime is a treat for the ears as well as eyes.

March 21, 2006

The sight of a soaring bald eagle has become much more common in the last few years, but always gives me a thrill. Adult eagles have a wing span of up to 7 feet and stand about 3 feet tall, so that either flying overhead or perched on a tree branch, they present an impressive picture. Adult males generally weigh about 9 pounds while females may be up to 13 pounds, and except for size, both look alike, with blackish backs and breasts and white heads and tails. Juveniles are a mixture of brown and white and don't acquire adult plumage until they reach sexual maturity, at about 4 or 5 years of age. Bald eagles can fly to an altitude of 10,000 feet, and during level flight, can achieve speeds of about 30 to 35 mph. They live along the coast and on major lakes and rivers where they feed mainly on fish, and have hunting territories of about 10,000 acres.

The bald eagle is found only on the North American continent and became our National emblem in 1782 when the great seal of the United States was adopted, Its Latin scientific name indicates that it is a sea eagle with a white head, and it was dubbed "bald" during a time when that word often meant "white," not hairless. About half of the world's 70,000 bald eagles live in Alaska, and combined with British Columbia's population of about 20,000, the northwest coast of North America is by far their greatest stronghold. Wild bald eagles may live as long as thirty years, but the average lifespan is probably about fifteen to twenty years.

Eagles feed mainly on fish, but waterfowl, small mammals and carrion supplement their diet, especially when fish are in short supply. Their keen eyesight allows them to spot a fish coming to the surface of the water at distances up to a mile and they swoop down to seize it in their talons. The bird can lift about five pounds, but has been seen to swim to shore with a heavy fish using its strong wings as paddles. Watching the birds feed below the dam in Prairie du Sac has even become grounds for an annual festival.

Eagles sit at the top of the food chain, making them quite vulnerable to toxic chemicals in the environment. Following a dramatic drop in eagle population early in the 20th century, the Bald Eagle Protection Act which prohibits possession of an eagle alive or dead without a permit was enacted in 1940. Then, in 1978, the bird was listed as an endangered species, although by 1995, this designation was upgraded to "threatened" as its numbers increased. Now, it may be delisted in the next year or so, although it will still be protected by the Migratory Bird Treaty Act and the Eagle Protection Act. Possession of a feather or other body parts of a bald eagle is a felony with a fine of up to $10,000 and/or imprisonment, although Native Americans are able to possess these emblems which are traditional in their culture.

Bald eagles mate for life, although if one dies, the survivor will accept a new mate. Some nests have been used for more than 35 years and the annual addition of nest materials can lead to enormous structures, some as tall as 20 ft. and 7 feet across. Our local nest located a few miles south along the river bottom is probably about 8 feet high and five feet across and seems to be two-tiered. Modern technology is revealing fascinating details about the eagle's home life, as cameras have been installed in several areas, allowing observers to monitor nests without disturbing the birds. This is feasible because the camera can be put into place during the winter with an excellent chance that the birds will return.

At one site, Charlie Todd, a wildlife biologist with the Maine Dept. of Inland Fisheries and Wildlife, reports that the pair he is watching began regular visits to the old nest around the first of February, carrying in new branches and arranging them. When they had raised the nest platform about 6 inches, they began adding small twigs and grass as lining. After these improvements, the female began sitting in the nest for lengthening periods, although regular absences indicated no eggs had been laid. Even mated pairs participate in spectacular courtship displays at this time. They soar to great heights, lock talons and cartwheel at dizzying speed, breaking apart just before hitting the ground. The pair takes turns in incubating the eggs, never leaving them exposed for more than a minute or two, and carefully turning them until they hatch in about 34 days. In four months the young are testing their wings and by winter they are ready to gather with others of their kind along open waterways that offer sufficient food.

It is against the law to approach the local nest but anyone can watch the process on the internet, calling up any of the several web cam sites. These include those of the Northeast Utilities, National Wildlife Federation, and the Blackwater National Wildlife Refuge, on the eastern shore of Maryland, <http://www.friendsofblackwater.org/camhtm2.html>, our favorite. Good watching!

Who knows what the weather will be like when you read this, but even if there is snow on the ground and a frigid wind blowing, there is little doubt that spring is here. Geese and cranes fly overhead, and robins, redwings, and song sparrows are not only back, but singing, and some are even staking out their territories. As I write, the temperatures are on the rise, thunderheads are glowering, and the trails beckon invitingly. Spring beauties are pushing through the ground debris and clumps of hepatica buds are ready to respond to the first extended warm period.

All winter I have worried about the many birds that left us last fall, headed for more hospitable climates to the south. Then came the hurricanes, one after another, striking the entire gulf coastline. Considering the catastrophic effects on the human population of those regions, it has seemed almost trivial to be concerned about what happened to the birds, but the worries persist. Migration is a dangerous process at best, as severe weather is just one of many potential threats faced by these birds, which also must avoid predators and such manmade hazards as tall buildings, windows and communication towers. From a bird's point of view, hurricanes can be deadly. Land birds may die at sea. Seabirds from the gulf and ocean may be driven onto land. Weary migrants may perish or end up in strange places, unknown to them. Coastal birds could be blown far inland. Once the storm passes, remaining birds find that food is scarce or nonexistent. Still, birds have developed techniques for surviving such storms. They have extremely sensitive inner ears, able to detect very small changes in pressure, and change their behavior accordingly. By the time hurricane season hits most baby birds have matured and are quite capable of flying long distances quickly. Migrants almost always experience at least some bad weather, and know where to find alternate routes to avoid it. So when they detect drops in barometric pressure or high winds that precede an approaching storm, they try to steer clear of it.

Each year, migratory birds cross the Gulf of Mexico during the hurricane season. Birds wait for favorable winds and weather before taking flight, so they won't try to fly during a hurricane. If a migrant lands at a spot that has been devastated by storms, it will continue onward in search of better stopover areas. Unfortunately, sometimes they get caught in bad weather while crossing open water. Although migrants have enough fuel reserves in the form of fat to make the 600-mile Gulf crossing in favorable winds, they may not have enough energy to survive if they have to fight against headwinds.

During windstorms birds may sometimes be seen flying overhead at high altitudes where the upper atmosphere is often comparatively quiet, with the disturbance confined mostly nearer the ground. This is the case even during many hurricanes. Sometimes, when they do get caught unexpectedly in a gale, they have been observed to rise high in the air, facing into the storm, making a little progress forward as well as upward. Then the birds will suddenly drop and let themselves be carried in the direction of the blowing wind, before repeating the process and gradually working themselves to the outside of the storm and calmer air.

Birds on the ground tend to stay low when heavy storms hit, taking shelter under rocky overhangs, in caves and other naturally safe areas, or hide in hollow cavities in large trees likely to survive the winds. Many move inland from the coast where the fury of the storm tends to lessen. Phil Berry, a birder in Gulf Breeze, Florida, wrote to Journey North on September 30, 2005: " I live on the intercoastal waterway, within sight of the Gulf. We have experienced fallouts (large invasions) of several species of migrating warblers. Shorebirds have left the beach and have been in my back yard since Sunday morning...to find food. Other than the above, things appear normal. My hummer feeders were left up during the storm and were well-used."

Ted Below, a bird expert who keeps track of coastal bird populations for Rookery Bay National Estuarine Research Reserve on Marco Island in Florida reported that while they did find many dead birds following the hurricanes, the figure represented less than 1 percent of the region's bird population. Of greater concern was the destruction of many hundreds of active nests still on the beach, making last year one of the worst for nesting in recent memory.

Recent e-mails received from hummingbird enthusiasts along the coastal areas are encouraging as they report birds are arriving at feeders on schedule. One wrote, " My best friend lives in Biloxi. When I was finally able to call her to check on her a few days after Katrina, she told me her yard and feeders were full of hummers. She had a tree down and part of her roof was gone but her hummers were there." Birds and hurricanes have coexisted for millennia, and given the chance, healthy bird populations can rebound from the effects of such natural disasters. We will be waiting anxiously for the return of our nesters.

March 7, 2006

It is sometimes easy to forget that we have a marvelous wetland community almost outside our back door. The Wisconsin River and its surroundings are home and stopover for a great number of animals, birds, and other wildlife, and the areas along Kennedy Road provide good access to view their activities. Early spring is a particularly good time to visit, as Canada geese, sandhill cranes, all sorts of ducks, and even swans can often be seen. This week it was trumpeter swans that drew Bill and me to the area, and the fact that we are seeing these majestic birds is a story worth telling.

Of the seven species of swans in the world, the tundra swan and the trumpeter swan are native to North America. In addition, mute swans, very large and aggressive birds introduced from Europe and Asia, can be sometimes seen. They are best distinguished from native swans by the knob at the base of the upper bill, and the color of the bill itself, which is orange, with a black tip and base. Mute swans are beautiful, graceful birds with little fear of humans, and have become popular in many communities. Despite their aesthetic appeal, mute swans are causing increasing problems, as their large numbers have over-grazed many wetland areas, destroying habitats for wetland species and driving natives from their nesting and feeding sites.

The native tundra swan has a 6 to 7-foot wingspan, weighs 13-20 pounds, and stands about 3 feet tall. It breeds on the high tundra across the top of North America and winters some 3,500-4,000 miles away along both coasts as well as where open water is available in the interior West and around the Great Lakes. Also called "whistling swan", this designation referred to the sound made by the slow, powerful beating of the wings in flight, and not to the voice of the bird. Tundra swans can often be seen in the upper Midwest during spring and fall migration.

The swans that we observed this week were much more exciting, however. The trumpeter swan is the largest waterfowl species native to North America and has a wingspan of up to eight feet. An adult stands about 4 feet high and can weigh 30 pounds. It has a broad, flat bill with serrations along the edges that strain water when the bird eats aquatic vegetation, and its long neck allows it to uproot plants with ease. Observers have described the bird's call as resonant, deep and loud, sonorous, and trumpet-like-hence its name, trumpeter swan.

Trumpeter swans usually don't nest until they are four to six years old but then mate for life. The nest may reach a diameter of 6 feet or more and is placed on top of muskrat or beaver lodge if available, or they will pile sedges and cattail tubers into a mound. When the cygnets (baby swans) hatch in June, they weigh about 7 ounces but may gain 20% of their body weight every day. They are fully feathered by ten weeks and can fly at 15 weeks. By then, they can weigh up to 20 pounds.

Trumpeter swans were once fairly common throughout most of the northern United States and Canada, but market hunting and the millinery trade rapidly depleted nesting populations during the 19th century. They still nested in Wisconsin until the 1880s in all but the northeastern forested regions, but by 1900, it was widely believed that the species had become extinct not only here but nationwide. Fortunately, a small nonmigratory population survived in the remote areas of Montana, Idaho, and Wyoming, as well as in isolated parts of Alaska and Canada.

In 1935, the U.S. government established Red Rock Lakes National Wildlife Refuge in Montana's Centennial Valley to protect the remnant trumpeter population. Refuge personnel restricted livestock grazing and hay cutting in the marshes, protected the muskrat population for their houses, provided winter food, controlled predators, and more recently prohibited the use of lead shot and lead fishing sinkers, allowing the western population to rebound.

In the last ten years, the Wisconsin Department of Natural Resources has been working with Minnesota to establish a western Wisconsin/eastern Minnesota flock, hatching eggs obtained from captive birds and from Alaskan wild nests (with more than two eggs). They transferred newly-hatched cygnets to isolated sites where they were cared for and protected in heated overnight cages until well grown. At two years of age, they were released as pairs on carefully selected marsh sites, and since the birds typically "imprint" on their release area, these swans now return to these sites to nest. The goal was to achieve a population of at least 20 breeding and migratory pairs by the year 2000, and not only has this goal been surpassed but the restored Wisconsin flock has begun to use and re-use traditional migratory stop-overs along the Mississippi Flyway. Beginning in July of 1999, satellite telemetry has been used to determine the migratory movements and specific stop-over sites, and ten trumpeter swans have been outfitted with satellite transmitters that relay the birds' locations to overflying NOAA satellites.

We were tipped off to the arrival of these swans by Sally Konnak, a local bird enthusiast. She had a much clearer view of the birds than we did, counting 19 of them and observing the colored neckbands that half of them wore identifing them as released birds. She reported that the flock flew in around 11:00 A.M., rested and cavorted in the open water, and then rose into the setting sun to fly off up-river. She says it was a sight she will long remember.