October is the month that wildlife feasts on acorns. Acorns are, indeed, the food that fuels the ecosystem of our eastern forests. Most of North America’s vertebrate species and a tremendous number of invertebrates consume acorns. We can only hope that the sudden oak death, a fungus responsible for the death of west coast oaks, does not devastate our native oaks. This would portend a disaster much worse than the loss of the American chestnut of the past generation.
Other trees and shrubs produce fruits that are significant for the survival of wildlife. A number of these are soft mast species, high in carbohydrates, or sugars, which ripen throughout the summer. Examples of these sweet-tasting fruits include raspberries, blueberries, mulberries and black cherries. Not surprisingly, since birds have a poor sense of taste, these fruits are often low to the ground, and made available to mammals for eating and dispersal. However, in the fall, the strategy for plant seed dispersal changes. Fruits are produced adopting two patterns; one producing high-lipid, or fat, content, and the other producing low-fat content.
High-fat fruits rot quickly and must be consumed in a short period of time or else they will not be dispersed. This pattern is somewhat akin to ‘putting all your eggs in one basket’. Such plants that utilize the high lipid strategy include spicebush, flowering dogwood, sassafras, black gum, and Virginia creeper. For example, spicebush fruits contain 35% lipids by weight and flowering dogwood, 24%. These high quality fruits are ideal food for migrating birds since there is roughly twice the energy per unit of weight in lipids as are found in carbohydrates. So, in order to assure the migrating birds can find these short-term fuel reserves, many of these plant species undergo a very early leaf color change, known as a foliar fruit flag. In this way, it is believed these plants can better attract the migrant birds. This strategy invests a high level of metabolism in its fruit production, so few plants have adopted this pattern.
Most plants produce low-fat, fruits. Since these fruits last much longer, they can be consumed later during the winter months and still be viable. Examples of such low quality plants include greenbriers (< 1% fat), chokecherry (0-2%), hawthorn (1-2%) maple leaf viburnum, red cedar, and winterberry.
Sumacs present a variation of this theme. Although the lipid content of the fruit is high (over 20% fat), the periocarp, or fleshy fruit is extremely small compared to the large inedible seed. Thus, a lot of the fruits must be eaten before much energy can be gained. Additionally, the tannic content is high. Sumacs are one of the last fruits eaten, sometimes lasting several years before consumption, making it a survival food, much like the rock tripe is for humans.
While many animals are getting ready for winter, some are active in the birthing process at this time of year. Brook trout, for instance, are busy spawning in our mountain streams. The female makes a two-foot circular depression in the sand, about ten inches deep. Often, the spawning nests are made on the edges of deep pools. Using her tail, the female takes about a day or two to create the nest, with the male nearby, actively chasing away potential suitors from his mate.
Once the nest is completed, the spawning begins with the male forcing the female on her side, vigorously vibrating their bodies while the eggs and milt are deposited. Upon completion, the female moves upstream and sweeps her tail until the sand fills in the nest. The eggs will remain over-winter, not hatching until springtime, when they will wriggle out.
Black rat snakes are still hatching in October from the 5 –20 eggs laid in June and July, usually in rotting wood. In fact, it’s not uncommon to find black rat snakes, in the fall or early spring, climbing along tree trunks with open cavities that provide winter habitat.
By the end of the month, all snakes will be ensconced in their overwintering sites.
Wood turtles also are hatching from their June eggs, quickly proceeding to nearby waters. Turtles will over-winter in the muds of shallow water. The exception is the box turtle, which over-winters terrestrially under the soil freeze line, although they have been known to over-winter underwater.
We’ve all seen the bright orange salamander-like creature called the red eft. Red efts are the terrestrial stage of the red-spotted newt; a primitive type of salamander. Born as gilled aquatic newts with an olive-colored body with red spots, these larvae will live in the water for a year or two before they loose their gills, develop lungs, turn bright orange, and leave the water as terrestrial red efts. October is the principle month for the newts to change into red efts and leave their aquatic world. After three or four years as terrestrial inhabitants, the efts will return to the water as reproductive adults. They regain their olive-gray body background color and their tail becomes a flattened rudder. They retain their lungs, however, and come to the surface to gulp air for the rest of their lives.