Earth Almanac: July/August 2007

Fox in the Grass

Now young fox snakes, newly emerged from eggs and less than a foot long, are hunting amphibians and juvenile rodents. As they mature they’ll take larger prey—mostly mammals, which they kill by throwing coils around them and squeezing. There are two morphologically similar species—the western fox snake, found in farmlands, prairies, and open woodlands of the eastern plains and western Great Lakes states; and the lighter, redder eastern fox snake, found in and around marshlands of Michigan, northern Ohio, and southern Ontario. These large, beautiful constrictors are rat snakes, but they acquired their more attractive name from a decidedly unattractive defense mechanism. Pick one up, and it will hose you down with musk that smells like fox urine.

Little Big Fish

You’re waist deep in the sea anywhere from Maine to the Yucatán when a red-tinged, 25-foot shadow veers toward you. Now it’s 20 feet away and closing fast. As you splash shoreward you can almost hear the theme from Jaws. Amoeba-like, the apparition swells and splits. You have crossed the path not of one fish but of thousands, none longer than four inches. They are bay anchovies (a.k.a. “rainbait,” because they often dimple the surface for acres). Grazing on zooplankton, these superabundant, semi-translucent specks of protoplasm fuel vast ecosystems—from seabirds to tuna, mackerel, striped bass, weakfish, jacks, and bluefish, as well as the pelagic fish and mammals that eat these predators.

Look for bay anchovies in late summer sandwiched between surface explosions of game fish and dipping, screaming terns and gulls. Catch one of the game fish and it will disgorge anchovies all over the inside of your boat (where many will dry and stick as if glued). Bay anchovies are extremely tolerant of changes in salinity and low oxygen levels, sometimes moving into warm estuarine waters that are almost fresh. In one experiment, survival of young increased as dissolved oxygen decreased, presumably because oxygen-depleting organic matter was feeding their zooplankton prey.

Summer Treats

There are few places you can go in North America in high summer and not find huckleberries. Huckleberry plants, which unlike blueberries don’t bear their fruit in large clusters, represent many species with a confusing array of names. For instance, two distinct species—one that grows in the East, the other in the West—are both called “black huckleberry.” The same with two species called “dwarf huckleberry.” Eastern species include blue huckleberry, Confederate huckleberry, woolly huckleberry, and bear huckleberry; western species include red huckleberry and, perhaps best known of all, mountain huckleberry. Huckleberries are less popular for cooking, but their sweetness makes them ideal for eating on cereal or with milk. One of the great joys of summer is picking huckleberries with kids and dogs. The former will solemnly inform you, through black-stained lips, that all the berries are going into the bucket; the latter will pick them one at a time—gingerly, with their front teeth.

Pied Pipers

In shallow fresh water throughout most of North America, pied-billed grebes are incubating eggs or fledging young. “Pied,” meaning multicolored, as in “pied piper,” refers to the thick, bluish, black-banded beak of breeding adults. Flush a male or female from the nest, and in one quick motion it will cover the eggs with vegetation. Then it may try to decoy you with a broken-wing act. Warmth from the decomposition of nest coverings is thought to help with incubation. Immediately after the young break out of the eggs they seek another protective covering—the wings of their mother or father. A parent will even dive with them there. Undisturbed, pied-billed grebes ride buoyantly on the surface, but when danger threatens they may swim just below, revealing only their eyes and nostrils.

Brilliant Flashers

In virtually any North American woodlot, summer is the time to go “sugaring” for underwings, a genus of owlet moths long associated with death, misfortune, and love. Species include the dejected underwing, mourning underwing, forsaken underwing, widow underwing, betrothed underwing, sweetheart underwing, and bride underwing. Excepting the Saturnids (which include lunas and cecropias), few of our moths are larger or more striking. Unlike Saturnids, underwings feed as adults; also unlike Saturnids and most other moths, their forewings are drab, blending in with tree bark so well the insects are rarely seen unless disturbed.

Then they expose brilliant underwings, presumably to startle predators or offer nonvital targets. Mix brown or white sugar with beer, rum, or wine; add vinegar, malt, and molasses until you get a semi-fluid paste; then paint it onto tree trunks at dusk. If one side of a tree is artificially illuminated or buffeted by wind, paint the other side. Moths won’t stick to this cocktail, but you will be able to watch them feed. In the flashlight beam their eyes blaze, and the colors of their underwings appear almost electric.

Back From the Dead

In summer young black-footed ferrets—apparently descended from Siberian polecats that crossed the Bering land bridge—venture outside their dens to play, arching their backs, wrestling, and hopping backward. Your chances of seeing this, North America’s rarest mammal, are virtually nil, but they wouldn’t have been great even before humans poisoned off most of its prey (prairie dogs) and replanted most of its short-grass-prairie habitat to alien grasses. So just knowing these mostly subterranean, mostly nocturnal animals are out there probably will have to be enough. And that’s a lot, because in 1979, when the last known ferret died in captivity, the species was presumed extinct.

Then, two years later, it was rediscovered by a Wyoming resident named Skip, who collected a specimen near his home in Meteetsee; Skip was a ranch dog. Since then, in one of the great success stories of the Endangered Species Act, captive-bred black-footed ferrets have been widely reintroduced in Arizona, Colorado, Montana, South Dakota, Utah, Wyoming, and Mexico. The estimated population in the wild is nearing 1,000. The species’ future has brightened with short-grass-prairie restoration and a scaling down of the war on prairie dogs.