Earth Almanac: July/September 2003

Blood of the Great Bear

In autumn, the constellation Ursa Major descends from northern skies to pad along hardwood canopies, leaving them bright as he fades into dawn. According to American Indian lore, ancient hunters killed the Great Bear, and the carcass bled on maples, sumacs, dogwoods, sweet gum, black gum, sassafras, and the like, staining them crimson. When the hunters cooked his flesh, the dripping fat stained yellow the leaves of such trees as aspens, birches, hickories, elms, beeches, cottonwoods, and willows. This explanation is no more fanciful than the currently popular notion that autumn leaves are tinted by freezing temperatures. Foliage is dulled, not colored, by Jack Frost. Reds are brightest when sunny days are followed by cool (but not freezing) nights. Under such conditions, sun-made sugars are trapped in the leaves, where they form the red pigment anthocyanin. Leaves that appear yellow are no less so in spring and summer. It's just that the yellow pigments—carotenoids and xanthophylls—are masked by the green pigment chlorophyll, which breaks down with diminished sunlight. Find maple leaves that are still green, and tape black paper over parts of them. Shielded from sunlight, these parts will turn yellow while the leaves' exposed parts will turn red.

Wafting South

Throughout most of our nation, buckeye butterflies are making their way south, sometimes in concentrations that rival the famous fall migration of monarchs. Look for these midsize butterflies in clearings and along meadow edges as they fuel up on the nectar of asters and other late-blooming wildflowers. Often they'll be perched on a protruding branch or the ground. If another insect passes close by, they're likely to give chase, then return to their posts. The six striking, multicolored eye spots—two on each hind wing and one on each forewing—are thought to frighten insectivorous birds. Adults live for only about 10 days, but butterflies of the season's last brood can overwinter if they make it to southern states and countries. In spring, buckeyes breed themselves back to their summer habitat, rolling north in waves of successive generations.

Flat on Their Sides

When the first nor'easters of fall send weakfish, bluefish, tuna, striped bass, marlin, and other Atlantic predator fish streaming south along the continental shelf, winter flounder—a.k.a. mud dabs, blackbacks, lemon sole—begin their own migration, easing in from deep water to bays and estuaries from Labrador to Georgia. Here, protected from frigid water by antifreeze in their blood, they'll spawn in midwinter, and their eggs will sink, unlike the buoyant eggs of most other marine fish. Winter flounder rest on the bottom, venturing higher in the water column less frequently than more piscivorous members of their order. Lying on their white blind sides and gazing up with bulging eyes that, during fryhood, have migrated to the right side of their heads, they are perfectly camouflaged against (or in) mud, sand, and weeds. The first—and only—thing you are likely to see is their eyes. Winter flounder lack the large, toothy maws of halibut and fluke, and their thick lips are permanently puckered, as if waiting for a kiss. Few fish are better eating, and now is the time to pursue them. Use small, long-shanked hooks. Sea worms work best, but garden worms are nearly as effective and easier to come by. Paint your sinkers red.

Bloom of Sea Spray

The sky is unblemished cobalt; the air, still and fragrant with the scent of tidal flats and sun-baked driftwood. So what are those curtains of blue-gray spray rolling across the Atlantic shore? They are the tiny flowers of a low, erect perennial called sea lavender, or marsh rosemary. From Labrador to Florida, they brighten salt marshes and wet meadows in late summer and autumn. Their thick rootstocks have a powerful astringent once used to treat dysentery, hemorrhage, and bad breath. Like other native plants of marine wetlands, sea lavender can be wiped out when humans, in vain efforts at storm-surge flood control, block tidal flows, thus creating monocultures of invasive phragmites.