"If you’ve seen one squirrel, you’ve seen them all." …
Betty Meredith, 1957, et seq.
(Jan, 2012) Anno Domini 2011 has slipped away into the mists of Times Past, as years do. We were taught in school that time is immutable, and that it has flowed by like a river at a constant rate since the universe was formed. As a child, my elders told me that happened 6,000 years
ago; my third grade science book erased that number from my memory and inserted one million. By the time I got to college it had grown to a billion; in graduate school, George Gamow told me it was 4 billion, and several years later Stephen Hawking corrected me and raised it to 12 billion. Just to be sure I had it straight, I checked Wikipedia yesterday and found it had grown to
13.75 billion, plus or minus a few millennia.
The crowning assault on my bewildered brain came last night when I watched an interview of Lisa Randall, an attractive young woman who teaches physics at Harvard and is so smart it makes your head hurt to listen to her. She said if the Higgs boson is discovered it may mean time is not constant after all. Or at least I think that’s what she said… I’m not
sure. In a way, I hope she’s right; it would confirm what I have observed lately, that each year goes by faster than the previous one. Last year I was still writing 2010 on checks after my birthday, and that was in May. I despair to think how long it will take me to realize it is 2012.
I was thinking about time and all of that this morning when I came into the kitchen, but it didn’t seem like a productive way to start the day, so I got some coffee and started searching for something less strenuous to think about. The bird feeder outside the window was no help. Last winter I was seeing from 15 to 20 species of birds in the yard each
morning, and many of them were northern visitors such as purple finches, pine siskins, red-breasted nuthatches and tree sparrows, but this winter I haven’t seen more than 12 species in one morning. Perhaps this is a reflection of increasing decrepitude on my part, but that’s not the entire explanation. The Audubon Society held its annual Christmas Count last week, and the
results were disappointing. I saw 36 species on the Gettysburg Battlefield, mainly because I was accompanied by a very pleasant young man whose eyes and ears are a lot better than mine. But the number of birds seen by the other groups participating in the count was significantly lower than it has been in previous years. Ecologists know that many of the winter birds have
irruptive populations… i.e., their numbers fluctuate from year to year… but with the environment under increasing stress, any decline in numbers is worrisome.
On this particular morning, I had an idea why there were no birds in sight. Two days ago I was watching several small birds pecking about when suddenly they all flew off in a panic. A second later a big Cooper’s hawk sailed into the tree and perched just above the sunflower seed dispenser. It was a spectacular sight… almost two feet long, with a
blue-gray back and wings, pale red stripes over a white breast, and long, curved talons designed for killing smaller birds. I called my wife; she was reluctant to leave the bacon on the stove and grumbled something about "if you’ve seen one bird, you’ve seen them all," but even she was impressed when she saw it. The hawk has been around all year; I saw it fairly often this
summer and fall, usually stalking flocks of starlings or pigeons. This was the first time I’d seen it in the yard since last winter.
If the birds are having a bad year, the same cannot be said of squirrels; they’re having a banner year. I can recognize a few of them; one has a broken tail, and another is larger and more aggressive than the rest. There are several smaller ones that were born last spring, and are still learning the fine points of nuisancedom. One of them stands out
because it is solid black. The first time it came to the yard I called my wife away from the stove again, and got the same result as with the hawk, but when she finally came and saw the squirrel she agreed it was cute. She appears to like it better than the hawk, because she has told several people about it.
Years ago there was a story in Life magazine about someone in Michigan who gave a black squirrel to someone in a town in New England somewhere, and after a while that town became famous for having black squirrels everywhere. There may have been some factual basis for the original story, but it got exaggerated beyond all reality and now whenever you hear
of a black squirrel someone will say its ancestors came from Michigan. Since my black squirrel appeared last month, various people have told me there are populations of them in Frederick, Baltimore, Annapolis, Harrisburg and Washington, and they all came from Michigan. The truth of the matter is both simpler and more complicated. Hair color in animals is controlled by genes,
and melanistic (black) animals occur as mutant forms in most species, just as their opposite forms, albinos, do.
Black foxes, wolves, leopards, or mice are produced by normal parents, as was the albino deer that my sister photographed in her yard several years ago. That’s the simple part. The complicated part is how the genes work. Over a century ago, W. E. Castle discovered that the gray color of squirrels and mice results from each individual hair having bands of
black, white and brown; that is why it is such excellent camouflage, and also why it is so hard for an artist to copy accurately. Dr. Castle discovered about six different genes which produce these colors; since then, nearly 100 different forms have been found. The production of the color bands on the hairs works like an assembly line in which each gene must do its part in an
orderly sequence. If one gene is defective or mutated, then it can’t do its part and the assembly line stops. In the case of albino animals, the defective gene occurs at the beginning of the process, so no color is produced, even though all of the other genes may be normal. Obviously, the gene that causes black animals must block the assembly line much later in the process.
Obviously? Well, maybe not. I used to take two class periods to explain it when I was teaching genetics, and I thought I understood it then. Now, I just read that the defect in the gene for melanism has been mapped, and a small section of its DNA was found to be missing. It seems that in the 14 years since I retired, time has speeded up and left me
behind. The Preacher who wrote Ecclesiastes was wrong. There is something new under the sun, practically every day. So, enjoy the New Year. It will be different.
Read other articles by Bill Meredith