Christine Barnes is a Northfield resident and a volunteer at St. Marks National Wildlife Refuge. It is evening. In the pen, seven restless Whooping Cranes peck at snails, insects and other bedtime snacks as they make their final forage for the night.

On watch this late afternoon, two crane handlers wait patiently in the blind. Chapter 1 in the Crane Safety Manual, required reading for the birds, states clearly that at night, each crane will take its place on the submerged oyster bar for safety. After weeks of modeling by Operation Migration staff, this is an expected behavior. As the evening closes in, all is well. One by one, the cranes begin to line up in the water. Suddenly, one of the two young males takes flight, and lifts gracefully out of the pen into the open marsh. Alas, six other teenage rebels follow close behind in a full-bore jailbreak.

The rising moon glows over the wetland. Reluctantly, the surrogate parents don the crane outfits, not without trepidation. Darkness has set in. It is too late for the cranes to fly back to the pen. With their safety in the balance, only one option remains: these two surrogates must join the birds in the swamp - for the night.

"Oh darn," thinks the redhead with a grin. "Over night in the saltmarsh - how many people in the world ever get to do this?!!?" The magic hours pass. Parting clouds reveal a nearly-full moon and a multitude of stars. The water in the marsh doubles the pleasure, reflecting the roosting cranes and the artwork in the sky. Barred Owls, coyotes, and Clapper Rails call throughout the night, frogs chortle romantically. The cranes are closer to wild than they were yesterday, safe until daybreak.

Like all teenagers, young cranes do not always know what's best. Not that we know better - but the mission of Operation Migration staff is to shepherd the cranes to the impending pull of spring migration when they will be officially 'wild', no longer 'managed'. Spending another night outside the protection of the crane pen is not an option.

The next evening, out in the vast, still, wetlands, before the moon rises to light the way for the creatures of the night, there lurks a rustling, quivering, amorphous monster of the swamp, blue as midnight. It lies in wait, prepared to frighten the color out of whatever comes its way - its sharp, harsh bellow booms through the unsuspecting twilight and, as it rises from its hiding place, its full monster profile strikes terror in the hearts of all hapless beings nearby.

Flash back forty years: Bev Paulan, a young girl with tangled red hair blowing in the wind, trots along on the Wisconsin sand prairies of Aldo Leopold country, a place that for her, symbolizes wilderness. She hears the primeval call of Sandhill Cranes, still in recovery from habitat loss and population decline. She knows she walks on hallowed ground, and that she must step carefully for the rest of her days. Bev is bold, fearless and fiercely independent. On her tenth birthday, the interactive Dr. Seuss book All About Me offers a hint of things to come: in the centerfold, she is presented with a multitude of vocational options. She scrutinizes the opportunities, and makes her choice: "Nothing", she writes.

A good student and voracious reader, she devours books on science, biology, animals, birds, then DDT and its tragic and far-reaching effects. "Rachel Carson rocked my world." But it is an idea, a concept, not just one person, that ultimately influences her life: somebody needs to take care of the Earth.

When she is 14, she tastes a new frontier: her father gets his pilot's license and takes her flying. For a while, Bev maintains a traditional course - finishes college with a degree in biology, gets married, works in her husband's office, lives in a Chicago suburb. But by age 30, now divorced, she steps out the door into the sunlight and never looks back. No walls will define her boundaries, no office hours will bind her time, no typical, predictable life will unfold before her. Bev's passionate spirit is set free, and free it will stay. She pairs two loves: flying and nature. She uses her biology field skills to track animals for research and census, and helps with fire and air quality monitoring. She contributes to the Bald Eagle survey. She works in a wildlife rehab center and does outreach to children.

Now, some fifteen years later, Bev finds herself with the endangered Whooping Cranes, in charge of Field Operations, with an unstructured job description that taps her many talents. In the outreach program that teaches about the crane recovery project, she continues her work with children. In addition, she works a biological and geographical triangle from crane egg, to chick to teenager; from Maryland, to Wisconsin to Florida. She spends a lot of time in the crane outfit, training the birds as a parent would. At night, she is the dreaded swamp monster. In an ultralight, Bev will lead next year's crane chicks on their first migration to St. Marks.

We now return to the drama. As the evening sets in, the restless cranes fly out of the pen, into the wetland. Ever vigilant, shrouded in a rattly blue tarp with eyeholes, an air-horn in hand, in a full and terrible rush, Bev, the swamp, monster spins in spirals and makes more unholy sounds, and the errant, scared-white Whooping Cranes, thinking they were going to have another night out on the town, take flight with frantic wingbeats and return to the pen. It is here they will rest in the water, safe on the oyster bar, away from predators of the real kind, until a new day dawns. For this Keeper of the Earth, it is one more day, one step closer to recovery.