Earth Almanac: November/December 2005

Going Bananas for a Slug

The best time to find bananas in the coastal rainforests between California and Alaska is late autumn, when the weather is wettest yet still relatively warm. These bananas are animal, not vegetable, and you definitely don't want to eat them. They're slugs, the biggest in North America—the size, shape, and color of their namesake. The lives of banana slugs depend on the prodigious quantities of slime they constantly pump out. It repels and gags predators. And although a slug possesses both male and female sex organs, it mixes genes by finding a mate, which it attracts by spiking its slime trail with pheromones. Slugs are mollusks that retain vestigial though not easily seen shells, apparently remnants of those possessed by their marine-snail progenitors. Some land snails, which can't fit into their shells, are thought to be in the intermediate stages of evolution toward slugs. In 1986, after the University of California at Santa Cruz joined Division III of the National Collegiate Athletic Association in five sports, the iconoclastic yet ecologically literate student body adopted the banana slug as the school's official mascot.

Mini Duck

When ice clutches at the ponds of Alaska, Canada, and the northern- tier states, buffleheads—the continent's smallest diving ducks—sweep like windblown snow toward their winter range along our Pacific, Gulf, and Atlantic shores and on open interior lakes. Watch for them as they stage in sheltered bays. To get a sense of their size, consider that they nest almost exclusively in holes excavated in dead trees by northern flickers. The name bufflehead derives from “buffalo head,” a reference to the drake's disproportionately large head. Flight is low to the water, and, like that of their cousins the goldeneyes, swift, with rapid beats. But unlike goldeneyes, buffleheads' wings don't whistle, and unlike goldeneyes and other diving ducks, they can rise almost directly from the surface instead of having to run and flap across it. Finally, mated buffleheads are unusual among ducks in remaining monogamous. In a few days drakes will begin courtship displays—bobbing their heads, lifting their wings, and dashing about on short flights.

Horse Apples

After the foliage of other hardwoods has faded and fallen, the yellow leaves of the Osage orange brighten the otherwise drab landscape throughout most of our contiguous states. This large, thorny shrub—related to figs, not oranges—grows naturally in the Midwest and Southeast but, before the invention of barbed wire, was widely transplanted. Now the ground beneath stands of Osage orange is littered with large, multiseeded fruit, repulsive to humans but relished by squirrels and livestock. These “horse apples,” as they're called, apparently evolved with and were eaten by equines and ground sloths, which were extant in North America until after the arrival of humans and which may have served as the main seed-distribution agents. Pioneers extracted a yellow dye from the root bark. And the heartwood, stronger than oak and as pliable as hickory, was prized for making bows by the Osage Indians of Missouri and Arkansas. Even today this wood is the first choice for traditional archers.

Little Big Bird

From the Great Plains east, the tufted titmouse is even more active than usual as it forages among tree branches (sometimes hanging upside down in the process) or caches seeds by wedging them into bark. Now these loud cousins of the chickadee, with their jaunty crests and bulging black eyes, seem to seize command at feeding stations, shouting peter-peter-peter and, wings spread or quivering, lunging at other birds. With their winter food supply secure, they will be out and about even on the coldest days, traveling in small family flocks. But they are only recent arrivals to the north country. In 1929 the great ornithologist Edward Howe Forbush called the species “a mere straggler in New England,” explaining that he had “not listed it as a Massachusetts bird because although several sight records have been given me we have no record of a specimen taken in the state.” These days, perhaps because of the warming climate and the proliferation of backyard feeders, few, if any, New England birds are more prominent at this time of year.

Blazing Berries

From Newfoundland to Florida and west to Texas and Minnesota, partridgeberries are best appreciated when they shine through a carpet of dead leaves or the first dusting of snow. Despite the name, the pea-size fruits of this perennial evergreen herb are not particularly relished by partridge or other wildlife, and that's why they're still around in large numbers. Each of these scarlet berries has two “navels” left by the two white blooms that formed it. “Squaw vine,” as the plant is also called, was used by American Indians and early settlers to ease the strain of childbirth; women still take it for a host of gynecological maladies. Reach down and feel the hidden, ground-hugging vine. Partridgeberry, available at native-plant nurseries, does famously in terrariums, especially if you use a glass or plastic cover to seal in moisture. After a few weeks your berries may double in size.