Autumn’s Dream Coat
What a day! Looking up to the chilled sky this fall season it was so clear, stars seemed to be dancing across the early morning darkness. Oh, and the moon; it looked like the hand of the creator decided to use a highlighter to encircle the outside with a powdery glow. Later in the day I noticed a Turkey Vulture, affectionately known as a “TV”, creating patterns across this perfect fall canvas. TV’s belong to the family of Cathartidae, which is derived from the Greek kathartes, meaning purifier. The term reflects the usefulness of the vulture’s scavenging. Their digestive system is able to destroy many dangerous germs, including Cholera. The medical meaning of catharsis is purgation, especially of the digestive system. This fits the TV, since the vultures defend themselves by vomiting on their attacker.
As I watch them float in the blue sky, I do not think about their meals or habits. I just hope they will return from their migration next spring to do their cleaning thing. This is also the time for little birds to migrate. Thrushes, warblers, kinglets (which travel to Brazil) and thousands of other birds work their way Southward, eating as they go. Ice follows them, firming the edges of forest ponds. When the last flock is gone, autumn will be gone.
During these short harvest days of fall, there is a tremendous outburst of activity on the part of most wildlife. Trees scatter food everywhere on the forest floors. Hickory nuts, acorns, beechnuts, butternuts are prodigiously eaten and stored by many birds and mammals. Rich forage grows in bright colors; winter berries plump. Beavers pile up more food than they can use in the underwater caches near their lodges. Their favorite is Poplar bark. The tireless raccoon stuffs itself at night to store fat for the long winter’s rest.
The most dramatic change of color is our Pennsylvania trees’ autumn foliage display. Witnessing this metamorphosis, you can’t but marvel at its beauty. If you have ever wondered what accounts for all these autumn transformations, you are certainly not alone. The pigments responsible for the color of autumn leaves are the raw materials in nature’s palette. The leaves contain several pigments in varying amounts. These chemicals color the leaves, flowers, roots, and stems of the plants. The most important are the Chlorophylls, from the Greek chloros for green, and phyllon for leaf.
A second category of pigments is the Carotenoids. They are yellow or orange and derive their name for the Latin word, carota, for carrot. The Carotenoids come in two varieties; the Carotenes, which are usually orange, and the Xanthophylls, from the Greek, xanthos, for yellow-brown and phyllon for leaf.
In addition to the green, yellow and orange pigments, reddish-colored leaves contain Anthociyanins, from the Greek, anthos, for flower and kyanos, for dark blue. This group of pigments got its name from Cyanin, the first flower pigment who’s study began over 100 years ago. It was first extracted from blue Cornflowers.
In order for a leaf to stay green, the overpowering Chlorophyll pigment must constantly be synthesized to replace the amounts that are slowly destroyed each day. In the autumn, the metabolism of the leaf slows down and less Chlorophyll is produced due to the shorter days and cooler nights. The resulting food loss is that the leaf’s green pigment breaks down. This allows the Carotenoids, which have been there all the time, to shine. Now we get to see them as the Chlorophyll fades.
What a cool time of the year, just right for a walk, perfect for birdwatchers, and great for watching nature tucking herself in for the winds ahead. Enjoy!