A good naturalist would have noted the time, date, temperature … all the pertinent circumstances and details. I’m not a good naturalist. I can’t even remember the exact month let alone the day the barn swallows departed. 

I remember us sitting on the deck on that sunny and warm morning near noon, hearing the ever present screeching “CHEEPs” from the gutters above us, and from the nearby clothesline and roof peaks of the studio and wood shop. Above the bluestem of our adjacent prairie the swallows flew in their delightful dips and dives, before suddenly making an awesome aerial pirouette. Feathered jets, mouths agape, collecting ever present mosquitoes and gnats! It is suggested swallows may be among the fastest flying birds with estimates of 64 mph. And, they’re noisy. 

We were talking, my friend and I, having a sandwich, when we looked at one another sort of startled, for it was suddenly deathly quiet. Total silence save for the rustle of leaves in the breeze. Our piece of the prairie was completely naked of sound. Not one swallow sat on the gutters, eaves or clotheslines. The prairie was devoid of the swooping jet-like birds. We were left with an unexpected silence, an even louder silence than when a harsh prairie wind, one that whips branches of even the sturdiest burr oaks, suddenly dies. Just like that even those birds that had left the nest mere weeks before were somewhere off on a flight of more than 5,000 miles to places I’ve never been.

Ah, the mysterious nature of migrations. Especially those sudden departures. Even ornithologists with emeritus status, who’ve studied bird behavior throughout their lifetimes, agree. 

Collectively we seem to rejoice the spring migrations here in the western edge of the Mississippi Flyway. Around our part of the prairie we have hundred of thousands of snow and blue geese populating wetlands for a few days of feeding and rest come spring. A few years ago huge populations stopped just north of here, and last year we spent the first days of the pandemic lock down about 15 miles due east where a huge flock of both (along with some swans) took over a basic farm section in ghost-like seasonal wetlands. In years past we’ve been seduced by the historic gathering of sandhill cranes along the banks of the North Platte in central Nebraska, and we once caught what seemed like a million redwing blackbird murmuration above a bend of the Yellow Medicine River late one spring afternoon.

And, there is the pure joy of seeing the first huge pod of white pelicans suddenly in contrast to deep blue skies each spring. Shore birds wade wetland edges, while warblers and other songbirds dash from branch to branch even in our small grove. We delight when the seemingly same two pair of wood ducks come each spring in search of nesting trees in our grove. Each sighting regardless of the species delightfully fulfills the satisfaction of welcoming another spring to our collective souls!

Fall migrations? While we haven’t joined the serious bird watchers with high powered binoculars at the top of the Empire State Building in downtown Manhattan to catch the flecks of jet streaming warblers overhead, we have ventured to Hawk’s Ridge on the outskirts of Duluth to wonder as migrating raptors catch the currents above Lake Superior on a frosty October morning. Those are just a couple of instances of pilgrimages for the autumn migrations that seems less eventful. Mostly it’s here one moment, gone the next with little if any fanfare. Many of the redwings you see in huge murmurations in the spring seem to simply disappear from the wetlands as did the swallows from our Listening Stones Farm. Yet, for the past few days a growing murmuration of redwings have gathered here in our grove. Stragglers? Newbie’s from this summer’s hatch? Ah, the mystery!

Recent trips through the nearby Big Stone National Wildlife Refuge indicates that several species are gathering. We witnessed growing murmurations as we crossed North Dakota a few weeks ago. Soon on a warm, fall afternoon, gulls will glide over our prairie home in poetic symmetry, either as a flock or singular as if on a string, one after another. Over on Big Stone Lake you may catch hundreds of resting coots through the bright yellow autumn colored leaves of dogwood, and the skeins of geese are larger in numbers and ever more present. 

What we see here, though, is somewhat meaningless in the overall scheme of migrations, and after years of experience and knowledge of radar use what we see may be as interesting as it is inconclusive. “Studying the movements of one species, let alone the hundreds, is a fundamental challenge,” writes Kyle Horton of the Cornell Lab of Ornithology in an article published in Science Magazine. “Because the drivers of avian migration are so complex, we need a system that captures that complexity.” 

Successful migration requires coordination of a variety of physiological, behavioral and ecological systems. “Birds must navigate accurately using multiple cues, time their journeys precisely, deal with winds that may blow them off course, find food in transient and unfamiliar environments, and often re-engineer their bodies to store energy and save weight,” added Benjamin Van Doren, a Cornell co-author of the article with Horton.

The two say environmental drivers, such as temperature, atmospheric pressure and precipitation play important roles in determining when large groups of birds take flight. With so many intermingling factors, the ecology of avian migration is exceedingly complicated — in short, it’s hard to know exactly when birds of a feather will flock together. Then, suddenly disappear. Ah, the mystery!

Each year billions of birds navigate the skies on biannual migrations, traveling great distances at tremendous heights, some thousands of feet in a night’s darkness, back and forth between breeding and wintering sites that sometimes lay a continent apart. Like ancient humans crossing vast seas, some birds plot their courses using the stars. Others follow the ebb and flow of Earth’s electromagnetic field — using it not just as a compass, but as a kind of visual heads-up display to identify their position on the globe.

Ah, the mysteries! 

Here on the ground, on our small space of prairie-land, we catch only the hints, those moments of rest and rejuvenation. For the past week our grove has harbored those hundreds of redwings in an ever moving feast taken from an adjacent harvested cornfield. We sat on the deck earlier this week, Mary with her coffee and me with my tea, watching groupings from a few to dozens skitter from the treetop perches to the field, and back again. Ever restless! That afternoon, they were nowhere to be seen. The following morning, the murmur was as loud as the geese gathering in the wetland just over the rise. Then … they were gone.

On a drive through the nearby Big Stone National Wildlife Refuge, on the huge reservoir of damed water, thousands of coots bobbed in wind-blown waves. Warblers darted through the mullein and sumac. Will any be here this morning? Tomorrow? Will there be a sudden explosion of wings lifting all from the water, in seeming chaos, blocking the moon or sun, as some force beckons them into the air? Like the redwings here?

Beyond the mysteries I find a certain sadness about autumn migrations … a feeling so opposite that of the promise of summer felt during spring migrations when the arrival of snow geese are as welcomed as pasque flowers on a prairie hill. Now, though, it’s not unlike watching the taillights of your lover’s car disappearing down the road, a feeling that was so vividly realistic on the afternoon the swallows left so abruptly that they left behind such a startling silence. Or, of waking this morning to discover the grove was completely empty of the murmuration.