Welcome, sweet springtime!

March 20, 1996|By Barbara Tufty

WASHINGTON -- Spring arrives with a thousand different timetables. One occurs in early February with the thud of spiky seeded balls from sweetgum trees pushed out by rising sap and falling on the still frozen ground.

Spring also starts when squirrels spiral around and around the tree trunk in the first chase of spring courtship. Another spring arrives at winter's edge with the hooting of owls calling their mates in dark shadowy woods.

At a time while winter still grips the earth, the brown-purple hood of the skunk cabbage pokes up through the snow. This early vile-smelling plant creates heat from oxidation of its sugars and starches at temperatures sometimes 27 degrees above those of the air hot enough to melt its blanket of winter snow.

Early wildflowers

A few weeks later spring's arrival is marked on the forest floor with fragile wildflowers spring beauty, bloodroot, trout lily all blossoming before new leaves of overhanging trees unfurl and block out their sunlight.

The groundhog's spring comes when temperatures are just right to awaken him from his deep winter sleep. In a matter of a few hours, his body temperatures rise from about 38 degrees Fahrenheit to 97 degrees, and he breathes faster from 10 to 12 breaths an hour to 30 or 40 a minute. He shakes himself, then hurries out into the still cool world.

In the black soggy swamps, wood frogs start their mating calls BTC as dusk falls strange, poignant croaks that sound like ''geese barking.'' Later, the exuberant spring peepers trill out their melodious spring chirps from trees.

Scouting for nesting sites

In the air, birds announce their own spring timetables. A purple martin scout, journeying from South America, swoops over open fields to check out possible nesting sites. A scarlet cardinal suddenly sings out his ''Cheer-cheer-come-here.''

A robin, his breast turning rosy, chirrups his soft evening call; and a high note of a chickadee pierces the air. Even the scruffy grackle croaks his paean to spring.

In the oceans, spring triggers the journey of the great whale, singing their eerie songs as they ply from southern seas to the colder northern breeding places. Millions of baby eels wriggle from the Sargasso Sea in the Atlantic Ocean to the coasts of Europe and North America, where they work their way up the rivers to spawn. Salmons leap to their destinies up cold rushing streams of the North American northwest; while in the east, the shad slide and slither their way up many coastal tributaries.

Spring tide

As the powerful tidal wave of spring surges northward over the land and seas at 15 miles a day, its biological passion, chaos, cacophony swells louder as each organism expresses its own verion of spring with individual noises, colors, movements.

But one sole timetable remains formidably rigid through all this wild commotion: that of the astronomer who quietly calculates the exact universal minute of spring's arrival.

Spring comes to the Northern Hemisphere, he says, at the specific moment when the sun on its northern journey drops its ray directly upon the earth's equator. This year, that moment of spring's arrival was this morning, at 3: 03 a.m.

Barbara Tufty is a science writer and consultant.

Pub Date: 3/21/96

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