Wednesday, November 28, 2007

Queen of the forests

When our grandparents were children, the Queen of the Eastern Forests still reigned. The spreading chestnut, under which Longfellow's village smithy stood, rose more than 125 feet with a trunk 10 feet in diameter.

The American Chestnut was one of our most valued trees. Whole houses could be built from its fine, hard wood. Its fruit was a relished food – who hasn’t heard “chestnuts roasting on an open fire” and wondered what real chestnuts must have tasted like?

But around 1904, at a Japanese exhibit in New York, an Asiatic tree fungus escaped and during the next two decades wiped out the mighty chestnut from Maine to Mississippi.

Well, almost. The chestnut blight attacks only the above-ground parts of tree. Thousands of old chestnut roots still survive in the woods, sending up young trees that may rise 20 feet before being attacked and killed by the fungus. The trees are usually too young to produce nuts from which wholly new trees can grow. Thus, these ancient roots are hanging on for dear life, seemingly hoping for a miracle.

And a miracle may be at hand. Scientists are “backcross breeding” the American Chestnut with the Chinese Chestnut, which means they keep taking hybrids of the two and adding more American Chestnut genes by repeated crossbreeding to find the most blight-resistant strains. They hope to get a nearly pure American Chestnut that can withstand the blight and repopulate the eastern forests.

While there's little hope for the village smithy, “backcrossing” may one day return the spreading chestnut to its noble size and full numbers.

Monday, November 26, 2007

Vulching

We have a little Thanksgiving tradition that might leave many people aghast: We feed vultures.

The day after Thanksgiving about a dozen years ago, we decided that instead of throwing the picked-over turkey carcass into the garbage, we’d recycle it by placing it in the back yard for crows, raccoons, skunks, and even foxes to snack on. It turned out that nature’s waste disposal team showed up first.

For many winters, Turkey Vultures had been roosting a quarter mile from our house. Our back yard is their back yard, so to speak. So when we offered that “dead meat,” the sensitive Turkey Vulture noses soon picked up the scent. Vultures landed in nearby trees to eye the potential meal. Once they determined the scene was safe, they dropped to the ground and chowed down.

Each year since, we’ve placed our turkey carcass in the back yard and every time, vultures have showed up to feast. One year, more than 50 were on the ground or in the trees at one time.

About five years ago, Black Vultures appeared.

Black Vultures are common in the southern United States, but until recently, were rare in the Northeast. They have been extending their territory northward, probably as the winters get milder.

The Black Vulture is smaller in appearance, with a wingspan of just under five feet, while the Turkey Vulture has a five and a half foot wingspan. Despite this, the Black Vulture is actually heavier – weighing up to 4.4 pounds while the Turkey Vulture weighs four pounds. Those differences can be seen in flight patterns. The bulkier and shorter-winged Black Vulture needs to flap its wings frequently to stay aloft while the Turkey Vulture can spend long periods, simply gliding.

The heads are also different. The Turkey Vulture has a red, fleshy head while the Black Vulture’s head is gray. That is not always easy to see, especially at a distance.

Turkey Vultures use a keen sense of smell – very unusual in a bird – to detect carrion from long distances. Black Vultures must rely on eyesight. That’s why, quite often, Black Vultures will arrive after Turkey Vultures – or crows – have already discovered food. Being the more aggressive, Black Vultures quickly chase off the Turkey Vultures, or crows, and take over the meal.

This year, Turkey Vultures were first to spot our gift, but were so timid, most would not land. Soon, Black Vultures saw their cousins sitting in the trees, watching the carcass – what we call “vulching.” Much less afraid, the blacks zoomed down and began eating.

Despite competing for food, Turkey and Black Vultures often roost together, usually in tall evergreens. The birds at the top of the pecking order perch on the highest branches, while lesser birds are in branches below. Some authorities believe the top-most benefit from the heat rising from the bodies of the ones below. Those below often suffer the indignity of being pooped upon by the birds above. That’s why you will see vultures – and sometimes crows – with white spots all over their backs (as in the accompanying photo of Black Vultures in our back yard).

Incidentally, until recently, vultures – including their close relative, the California Condor – were grouped with the raptors, such as eagles, hawks and kites. Recent DNA studies revealed that vultures are more closely allied with storks, flamingos, spoonbills, and ibises.

Monday, November 19, 2007

The winds of autumn

March may come in like a lion, but there's at least a tiger roaring late each autumn.

The winds that wash away winter and bring us spring have their fall counterparts. They have equal force, but get less good press. The lack of song and poetry about this season of the year probably stems from our displeasure with the icy blasts that fold up the last hardy flowers, kill most things green and send birds scurrying southward. Only skiers could like this season, and then only because they know what's coming soon.

An optimist might say autumn’s winds are part of nature's way of cleaning house, of sweeping away the old and preparing for the new, the groundwork for a distant new season of growth.

But if that sounds like a lot of hooey, look at it another way: This cold, blowy, barren season is great for making us appreciate the spring and summer all the more.

Tuesday, November 13, 2007

Gliding through the night

The night holds many mysteries, not the least of which are its creatures. Most people live a lifetime without ever seeing a common neighbor, the flying squirrel, yet they are all about us.

Both the Northern and Southern Flying Squirrels are mini versions of their daytime cousins – about half the size of a Gray Squirrel. Big-eyed because they are nocturnal, they make use of a flap of furry skin to glide – not fly – a hundred feet or more. They eat the usual squirrel foods, like nuts, seeds, insects and eggs, though the Northern is said to have a fondness for truffles and other tasty fungi.

Flying squirrels were once much better known and appreciated, not as aeronautical wizards but as companions. As far back as colonial times, people caught them as babies and raised them as pets. One of John Singleton Copley’s most famous paintings, “Boy with A Squirrel,” shows Copley’s half brother seated at a desk with a pet flying squirrel alongside him.

All is not perfect in this man-rodent relationship, however, and flying squirrels will sometimes infest attics. A dozen or more might decide to spend the winter huddled together in the comfort of your home.

Tuesday, November 06, 2007

Troubled waters

Not all invasive plants are found in woods and wetlands. Aliens also harm lakes, ponds and streams. Witness water thyme, which a UConn professor called “one of the world's worst weeds” and the director of the Invasive Plant Atlas of New England described as “a thug.”

Imported from Africa as an aquarium plant, Hydrilla verticillata clogs lakes and streams, pushes out native species of plants, fish and birds, and can even halt boat traffic. Across the nation hundreds of millions of dollars have been spent battling water thyme, using everything from herbicides to a Hydrilla leaf-mining fly from Pakistan.

While one group of scientists looks at how to kill Hydrilla, another eyes it from a different angle. Researchers have found water thyme is rich source of proteins, calcium, potassium, lipids, carotenoids, RNA, DNA, magnesium, iron, vitamins B1, B2, B3, B5, B12, phosphorus, manganese, zinc, copper, cobalt, 17 amino acids, and essential enzymes. Some claim it's an effective muscle builder and energy enhancer. University studies indicate it may be an appetite suppressant.

And that's just for humans. The University of Florida has found that water thyme increases the yield of milk in dairy cattle and the egg-laying capacity of hens.

So maybe there's another answer to controlling this latest invasive thug: Let’s all eat it.