Foreword to Johnathan: Two human characteristics that do us great harm are Superstition and Ignorance. They are deeply imbedded in many of the people and dogma that surround us. It takes years to root them out. Therefore, the things I write to you have within them tonics meant to decrease one, the other, or both of these undesirable elements (no, not the people). Take these mental medicines, sometimes bitter, sometimes sweet and hope the elixirs do you well.
We have lived in this house in Mount Pleasant, Michigan more than twenty-five years. If you look at a map, the state consists of two peninsulas, the Upper and the Lower. The Lower looks like a mitten worn on the right hand. If the mitten should ever make a fist, we should certainly be crushed, because that is where our town is located. If this occurs you will note a decided drop in mail (in whatever form) from us.
Our house is on the northwest corner of two streets. It is not particularly distinctive on the outside, from the other houses in the neighborhood, except in one regard. When it was a little house it ran away from its mother, playing hide and seek. It came into the lot to hide not as the others had. They were taught to line up straight with the road. Ours, not knowing better, set itself down at an angle to the streets! Its mother never found it and so it stayed. By this circumstance we made a lovely discovery.
The two windows in the master bedroom are such that one faces northeast and the other southwest. During the delicious cool evenings of late spring and early autumn we can leave these open, and what a breeze wafts through the room over the bed! Joyfully, we can snuggle under just a sheet, or one, or two, or even three blankets if we wish. Then wondrous things occur, but need explaining.
Sol, our star, throws off trillions of photons every nanosecond in every direction. A photon is the smallest particle of light. This vast storm sweeps through the solar system constantly. Sol is at a focus of planets, moons, comets, meteorites, dust and debris. When the light from Sol strikes one of these bodies, the side of the object toward the great star is lit. The other side is in darkness.
Some evening when the sky is clear of softball-size hail or other nasty things go out and try to find the moon, our planet’s only natural satellite. If you see it, perhaps only part of it shines brightly (on truly dark nights you may also see the rest of the moon’s surface in very faint light: this is reflected light from the Earth called “googenshein”). The contrast between the lighted and unlighted parts is very clear. The line between the two is crisp. This line is called the terminator.
On earth the line between night and day is not as clear because of the atmosphere. Water and dust scatter the incoming photons. Nonetheless, this smudgy line separating sunlight and starlight is also called the terminator. When we can still see Sol, the terminator has not passed. At the end of night, if Sol has not risen, the terminator has not passed. How, then, can we tell?
If you live on a farm, you know the rooster crows at the first light of morning. Our house is not near a farm, but we have those wonderful open windows in the bedroom. When it is very early but still rather dark outside, far to the east the birds give out their morning song. They sing for about twelve minutes. Closer birds pick up the song. When they are through, our neighborhood birds begin. This morning there were robins, cardinals, blue jays, doves, a single blackbird and others in the chorus. When they were done, birds to our west took over, and so the song moved from east to west.
Each group’s start occurs when the terminator passes over them. On clear mornings, such as today, sound travels well, and the whole sonata lasted forty-five minutes (to my ears). On overcast, or rainy days, the ambient noise drowns out some of the sound. The songs seem shorter.
Before the summer equinox the songs began very early, say 4:30 a.m. and the local songs occurred before 5. After the equinox the days grow shorter; the sun rises later and so to do the songs’ beginning. Today the terminator crossed our yard at 5:10.
Our birds also have an evening song coincident with the other terminator marking the onset of darkness. Unfortunately, people are out and about, laughing, playing, mowing their lawns, and all but drowning out the concert. We may hear the local birds bidding us goodnight, but often we miss even that.
Morning and evening songs are common to many diurnal birds. The evolutionary advantage is to alert the others in one’s flock to start foraging, and to remind them of one’s territory. The early worm is often caught by an awakened bird. The evening song helps locate the other members of the group as it settles into a safe haven. This does not seem to apply to owls, being such solitary creatures, lovely prowlers of the night, but they are well aware of the passing of the terminators.
Our town is very close to the 45° north parallel of latitude. During 45 minutes of song, the earth has moved about 728 miles from where it started, as the earth rotates on its axis. Hold on to those tree limbs, birds!