Earth Almanac: May/June 2006

Audubon    May/June 2006

Fleeting Fliers

Do you miss those soft spring evenings when you could stroll or drive beside the lower Great Lakes or Mississippi River impoundments north of St. Louis without picking mayflies out of your hair or skidding on their squashed carcasses? Don’t. From the 1950s to the early 1990s populations of many species of Ephemeroptera, the most ancient order of winged insects, were reduced by water pollution. When water quality improved and oxygen returned to their larval habitat in lake and river bottoms, so did they, and with them were reborn aquatic and terrestrial ecosystems fueled by their rich protein. Mayflies—delicate and curved, with two or three tail filaments—are unique in the insect world in having more than one flight stage. The opaque-winged subimago emerges from the larval skin, and the clear-winged imago emerges from the subimago. Male imagos have longer forelegs, the better to clasp females during copulation. Neither winged stage has working mouthparts, for adult life is so ephemeral that feeding is unnecessary. 

Raising the Flag

The Louisiana iris, aptly named for the Greek goddess in charge of rainbows, actually includes five species. Audubon called one of these “Louisiana flag” when he painted it as a backdrop for northern parula warblers, and the name “flag” stuck for the entire genus. The largest and most abundant of the five is Iris giganticaerulea—the giant blue iris, which stands up to six feet tall with a blossom five or six inches across. Now, along marshy margins of saltwater bays, it is in spectacular bloom in hues ranging from white to blue to violet. Bitter and rancorous was the battle to make Iris giganticaerulea the state flower. Defenders of the reigning magnolia denigrated the iris as a dweller of rank swamps. “Lots of people already think that everyone in Louisiana lives in houses on stilts in swamplands and keeps an alligator as a watchdog,” sniffed one of their number. But the undaunted iris acolytes countered that the magnolia isn’t a flower at all and condescendingly proposed that it be redesignated the “state tree.” In 1990 an uneasy truce was reached with the magnolia retaining state flowerhood and the giant Louisiana iris being named the “state wildflower.”  

Comeback Kits

Though they were nearly extirpated from the East by about 1900, beavers—the world’s second-largest rodent after South America’s capybara—currently abound throughout the Mississippi River’s drainage and most of the rest of the continent. In spring beavers give birth inside fortresslike lodges made of sticks and mud. Kits arrive fully furred with eyes open, and they’re capable of swimming within four to eight days. Watch for them exploring the immediate neighborhood with their parents. At this age they are extremely vocal, whistling and whining and constantly demanding attention. Sometimes a kit and a parent will swim in circles, embracing each other and rubbing noses. If an adult female slaps the water with her tail, the entire colony will instantly dive. If an adult male issues this warning, some will dive. If it’s a kit, no one will pay much attention. Kits stay with their parents for up to two years, assisting with dam building, lodge maintenance, and infant care. 

Tongue-Wagging Turtles

Now, when the egg-laden females lumber out of still or dawdling water of the Gulf States and the Mississippi River valley from southern Iowa to Louisiana, is your best and probably only chance to see an alligator snapping turtle—the single extant member of its ancient genus and North America’s biggest freshwater turtle. Imperiled by river manipulations such as levees that speed water flow and block access to nesting habitat, the species will be given a modicum of protection this June under the Convention on International Trade in Endangered Species. Although it will try to bite you and can do major damage if successful, it has a sunnier disposition than the common snapper, to which it is not closely related. Hold it by the shell and it simply freezes with its mouth wide open. Unlike the common snapper, its beak is sharply hooked, it has three ridges on its carapace, and its eyes are set on the sides of its head instead of the top. It spends its days in the deeper parts of its domain, mouth agape and luring fish by wiggling a pink, tonguelike appendage. The biggest alligator snapping turtle on record weighed 316 pounds. Should you be seized with the sudden urge to pick one up by the tail, resist. Such handling, warns one turtle-advocate website, can “damage vertebrae”—yours and the turtle’s.

Calling All Owls

You can summon owls in any season, but there’s no better time than spring, when small mammals are abundant and active. In waning twilight take a seat in a meadow or forest clearing and squeak by sucking air between your lower lip and bottom teeth. East of the Rockies and in the Pacific Northwest you have an excellent chance of seeing a barred owl settle soundlessly onto the nearest limb and fix you with its black eyes. The barred owl lacks the ear tufts of the slightly larger great horned owl (which may also appear). The barred owl has a rich vocal repertoire that is often heard by day and that extends far beyond its familiar who cooks for you, who cooks for you all? It may suddenly break into demonic screams punctuated by maniacal laughter. Or it may mutter in churlish tones: old fool, old fool, don’t do it, don’t do it. Barred owls are particularly abundant in swamplands of the Lower Mississippi River valley, where they are closely associated with red-shouldered hawks, hunting most of the same prey. There is no apparent conflict; in fact, there have been instances where the two species have shared a nest, alternately incubating eggs.


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