I heard the call – a soft purring – before I saw the birds.

The sound transported me back in time thirty or more years, to when I was volunteering with a captive breeding project for endangered whooping cranes. In that project, sandhill cranes served as surrogate parents to endangered whooping crane chicks, and humans – impersonating sandhill cranes – helped with the early stages of the process; the flying lessons were, of course, beyond our ability. Dressed in grey smocks and equipped with imitation crane beaks, we taught the whooping crane chicks to find food and water. And during long sessions huddled on the floor of a dark pen, dipping the puppet beak into food or water and touching it to the tiny chick beak, I learned to make the low purring sound that cranes use to tell one another that family is nearby, and the world is safe.

That contact call was what I heard last week at Bombay Hook National Wildlife Refuge.

I never expected to see cranes in Delaware. While there are historic records of sandhill cranes on the Atlantic coast, a combination of hunting pressure and wetland loss drove them to extinction over a hundred years ago. So, after my summer with the crane project, travelling to see cranes in the wild meant going elsewhere. To Nebraska, to witness the immense spring gathering of sandhill cranes on the Platte River. To Florida, where a resident population of sandhills is so accustomed to humans that they graze on the median of interstates and stroll down suburban streets. To Lake Hornbarga in Sweden, where common cranes learned to eat the potatoes that were once grown to produce vodka. And to Wisconsin, where once a whooping crane flew directly overhead as I stood in a corn field.

And even though there have been scattered reports of sandhill crane sightings in Delaware over the past few years, I was still amazed to see a pair of them last week, feeding in the marsh at the back of Bear Swamp Pool. Long-legged and long-necked, with elongate wing feathers arranged into a “bustle” that drooped gracefully over their tails, they were taller and more elegant than the herons and egrets who kept them company. They were feeding voraciously along the marsh edge, the red crown of their heads often hidden among the grasses, occasionally purring to one another, until the moment when they raised their heads high and turned to strut one behind the other along a small strip of mud, giving the unison call of a mated pair. With that bugling call they summoned to my mind images of the cranes I’ve seen and those I’ve only dreamed about.

 Across five continents, cranes are woven into myths and folklore: they are, as Peter Matthiessen describes them, “The Birds of Heaven”.  In Japan they are considered holy creatures and were once believed to live 1,000 years. They are in fact long-lived birds, living until 20 years old in the wild and 30 in captivity, but their fossil lineage is even more impressive. The wing bones of a crane ancestor, found along the Platte River, on the bird’s current migration route, have been dated back to 10 million years ago, making them the oldest living bird species.  According to Japanese legend, if you fold 1,000 origami cranes – one for each year of the cranes’ mythical lifespan - you will be granted a wish from the gods, eternal happiness or lifelong health. From this comes the ritual of folding 1,000 origami cranes in supplication for the health of a loved one. Elsewhere, in the Chinese tradition, cranes are believed to carry the souls of the deserving departed to heaven.   

In my mind, I can choose to regard the cranes’ appearance at Bombay Hook as part of a natural process, of species seeking out new habitats in the face of change. But my heart reads it differently: as a moment of grace, and a glimpse of heaven.