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Earth Almanac

Bob and Weave
Life Guards
Beautiful Taste
Sweet Stink
Warm-Weather Snow
River Dance

 

Bob and Weave
In early autumn’s cool nights, eared grebes migrate from nesting habitat in British Columbia, Manitoba, the Dakotas, California, and New Mexico to staging areas in the West. These small, stocky waterbirds—“eared” because of the golden tufts that sprout behind the eyes during breeding season—are the most abundant members of the grebe family. Like loons, they regulate buoyancy by forcing air out of their feathers. Also like loons, grebes have heavy bones that make diving easier, and their feet are positioned far aft, facilitating fast swimming but requiring water takeoffs and rendering them awkward on land. By late October enormous numbers—sometimes half the continent’s population, or an estimated 1.5 million birds—will have piled onto Utah’s Great Salt Lake. As in other saline water bodies, they gorge on brine shrimp. Before their leisurely departure to winter habitat on the Pacific and Gulf coasts of the United States and Mexico, they’ll molt. Watch them on chilly mornings as they raise their rumps toward the sun, absorbing warmth through their dark skin.

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Life Guards
Across the continent black-bellied plovers are sweeping down from their breeding grounds in the high Arctic tundra of Alaska and Canada to take up winter residence on beaches from Massachusetts to British Columbia, along the Gulf of Mexico, and deep into South America. Because these quail-size birds are larger than our other plovers, they can better conserve body heat, an advantage that may explain why they range farther north than the other members of the family. Watch them as they alternately scamper and freeze on wet sand, gleaning crabs, gastropods, worms, and insects with quick thrusts of their thick, black bills. Approach too closely, and they’ll take to the air with whistled alarm calls, then circle around behind you. It is this wariness that preserved them—and to some extent the more trusting shorebirds, for which they served as sentinels—before the Migratory Bird Treaty Act of 1918 put an end to market hunting and, for plovers and most other shorebirds, sport hunting as well.

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Beautiful Taste
Jerusalem artichokes aren’t from Jerusalem, and they aren’t artichokes. “Jerusalem” may be a corruption of the Italian girasola, meaning “turning toward the sun,” because that’s precisely what these sunflowers do. Now, in most of the eastern United States, “sunchokes,” as they’re also called, are decked in bright-yellow flowerheads three or more inches in diameter. The stalks, which can reach heights of 10 feet, sometimes break under the weight of the flowers. Tubers weigh two to five pounds each and, when carefully washed, are every bit as flavorful and nutritious as the potatoes they resemble. Their carbohydrates, however, are in the form of inulin rather than starch. When the tubers freeze in the ground or when you chill them in your refrigerator the inulin converts to fructose, imparting a sweet flavor. They can be baked, mashed, fried, or eaten raw. Jerusalem artichokes were an important staple for American Indians, who transplanted them widely. For this reason no one can define the natural range, although botanists think it was probably the northern Great Plains.

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Sweet Stink
Not all skunks are portly, pokey waddlers—the image projected by the ubiquitous striped skunk. From British Columbia to Idaho and Wyoming south to Texas and Mexico, a smaller, quicker, longer-legged species is entering its breeding season. Unlike the striped skunk and the eastern spotted skunk, the western spotted skunk mates in autumn, and the fertilized eggs float around the uterus until early spring, when they attach to the uterine walls and resume developing. There is virtually nothing edible that a western spotted skunk won’t eat. Watch one hunt or forage, and you’ll be reminded more of a weasel or house cat than what you’ve come to think of as a skunk. Unlike the striped skunk, the western spotted variety is an excellent tree climber and an accomplished mouser. It’s almost worth the risk of getting sprayed to watch this stand-up comic perform its threat-display routine. First it will stamp its front paws. If you stand your ground, it will then stiffen and strut like a politician on the stump. Finally it will stand on its front paws, waving its butt and hind legs in the air. If you’re more than 15 feet away, you may or may not be okay. The odor of the spotted skunk is said to be “sweeter” than that of the striped skunk. But no one is saying “sweet” is good.

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Warm-Weather Snow
On hushed September mornings most anywhere east of the Mississippi, you may see snowflakes sailing along under a cobalt sky. Why don’t they settle? And why does the porch thermometer read 72 degrees? Catch a “flake” in your cupped hand, and you’ll see a tiny winged insect loaded down with wool-like wax. It’s a woolly alder aphid that has just left an alder and is en route to a silver maple (or, rarely, a red maple), where it will deposit its eggs. The eggs overwinter in bark crevices. In spring they hatch into larvae that mature to wingless females that feed on maple sap, then reproduce asexually, giving birth to live young. In late spring a new generation of males and females will grow wings and fly to alders to reproduce. Black carpenter ants, which feed on the honeydew produced by woolly alder aphids, jealously guard them from predators.

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River Dance
Throughout southern Canada and our contiguous states, except possibly Washington and Idaho, the long flight period of one of our largest and most spectacular damselflies is under way. After perhaps a dozen molts over a year or more, the predacious nymphs of the American rubyspot crawl onto river banks and anchor themselves to rocks and vegetation. In the warm sun their skin splits, and adults struggle out, pumping their wing veins full of hardening fluid. Both sexes have bulbous heads. Scarlet patches on wing bases usually signify a male, while the female’s patches are more often a subtle amber. The male’s thorax is usually metallic red, the female’s green or bronzy green. A male will wait on a mid-current rock, flicking his wings to warn off rivals. If he gets lucky, a female will allow him to clamp the tip of his abdomen to the top of her neck. She then curves her abdomen, attaching the tip to the male’s genitalia. Still coupled, they fly to the riverbank, where they detach, the male standing guard against predators while the female submerges and attaches her eggs to aquatic vegetation.

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