If you were dropped into an area without knowing where, you could figure out from the animals and plants where you were and what time of year it was.
This is fairly easy for familiar geographic areas and, even without a calendar, you should be able to judge the season and month fairly accurately just by looking outdoors.
The end of summer provides a number of such clues.
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Leaf-footed bug on jimson weed apparently feels no ill effects from the plant’s dangerous toxins.
Fruit ripening is a reliable means of judging the month, subject to weather variation. Changes in ginseng flowers over the summer indicate with bright red fruit that it is mid- to late August at our southwest Virginia farm at an elevation of 1,500 feet.
Migrating thrushes passing through soon should find these ground-level red fruits very attractive, as they do the bright red fruits of spicebush and cucumber and Fraser magnolias.
The green and spiny fruit of the Jimson weed is altogether different. Although some are still blooming, numerous fruits have been set from earlier flowers apparently pollinated by moths.
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William Dunson, Ph.d., professor emeritus of biology at Penn State University, splits time between Southwest Florida and his farm in Galax, Va. He can be reached at wdunson@comcast.net.
This weedy plant grows primarily in disturbed soils and is famous for toxins such as atropine and scopolamine, which have long been used by humans for medicinal and recreational purposes. However, consumption of this nightshade family member is dangerous although a variety of hemipterans such as the leaf-footed bug feed on the pod with no ill effects. It is possible they may use the toxins in their own defense.
Age and size of young insects are also seasonal indicators. Caterpillars in a late growth stage indicate the season is well advanced. The few Monarch butterfly caterpillars left at this time of year are in their last instar and ready to pupate. They seem to benefit from mown hay fields in late June, which provides freshly grown leaves during the last half of the summer.
The large tiger moth caterpillar, feeding on ironweed, is distinctive with its white spiracles along the side. These are entry ports for air, which is taken into the tracheal system for distribution directly to the tissues, a radically different method than our lungs.
Dragonflies also provide excellent clues to fall's approach. Watch the behavior of the common green darner, which is present in ponds until the end of summer when it begins to migrate south. In its place another large dragonfly, the shadow darner, emerges to fill the niche previously occupied by the green darner. It apparently is much more tolerant of cold temperatures than the green darner.
Dragonflies are generally creatures of warm days and curtail their activities as temperatures drop.
Cooling temperatures also have a big effect on reptiles. The northern water snake loves basking on a streamside rock during a cool day to elevate body temperatures and facilitate growth during times when the prevailing air and stream water temperatures are too low for much activity. Cloudy eyes indicate a snake will soon shed its skin and the warm sun helps accelerate the process.
The most highly anticipated events of late summer and early fall are the arrivals of migratory birds, especially flocks of bobolinks, which stop in our fields and feed to renew energy stores. The males have lost their breeding plumage and resemble females.
We planted acres of food and cover to enjoy their visits in the fall and spring. In early evening we watch the bobolinks and can the skies for migrating nighthawks, which are also moving south in large numbers in late August and early September. Since we are "snowbirds" ourselves, who will soon migrate to our winter home in Florida, we understand in some small sense what these birds are going through.
