It is nighthawk time, these birds as behave like atomic nuclei. Come to think of it, so do barn swallows, brown bats, cluster flies, the species dipteria in general, also sulfur butterflies and honey bees, behave like an atomic identity, a hive of mutual vibration.

Technically, nighthawks, as we call them in North America, are of that family of birds known to the wider world as night jars, or for a more erotic sentiment, goat-suckers, a bummer of a nickname.

Officially they are genus Chordeiles, related to the whippoorwill, and like swallows, nighthawks feed in flight, often in clusters. Farmers know this behavior in tree swallows as the birds work on insects that fly up in front of a tractor, insects quite invisible to the tractor engineer. To note I prefer the term tractor engineer to the more prosaic tractor driver suggesting I know something about the tractor.

This flight behavior can be unnerving as they zig and dive back and forth off the bow of the tractor while mowing hay, cultivating potatoes, planting corn, the circling blitz of these birds.

The European handle goat-suckers has been around since the Middle Ages, a body of lore and witchcraft attached to this bird’s rumored habit of sucking goats of their milk in the night. Apparently goat milk was missing at the morning hour so obviously something was stealing it, why not blame these night-prowling birds.

It is the habit of nighthawks, for so they are named, to work the last strands of the evening light. Unseen from the human perspective is the converse traffic of equally low-light-enthused insects. Mating, foraging, migrating during the hours of reduced heat, reduced stress, less predation, except for this species adapted as owls to low-light conditions.

As explains why night jars … night hawks, whippoorwills are not commonly seen during broad day. The same adaptive eyesight of owls adjusted to low light, to suggest a corollary discomfort during broad daylight.

In modern American cities a culture of motorcycle practice exists known as nighthawks who prefer to ride and prowl the deserted night streets of big cities on their exotic machines.  These are generally the exquisite and nimble Jap bikes, so hi-revving as to suggest whiney.

I have been to the big town late at night enough to appreciate this solitary pleasure, driving those same streets now safe from idiot motorists, even safe from cops who often ignore behavior including speeds to gain a ticket in broad daylight. A certain delicious irony exists in the isolation and loneliness of a metropolis in the range of the far dark.  Elementary research suggests this nocturnal habit as applied to motorcycles is the more inclined to those hyper bikes and classic Brits, and is not the medium of Harleys.

As with nighthawks, a certain nimbleness defines the performance. For the sake of green philosophy I’ve long thought this same relish of the dark city would be great fun on a quick and equally exotic bicycle.

Nighthawks is an attractive family of birds despite their secretive habits, so secretive even their nesting sites are seldom seen.  In Europe, they migrate out of North Africa in the spring, where they and other song birds face increased loss of habitat as well as predation of the birds themselves. It is a sad mark of the human suffrage when garden-farming people resort to song birds for food protein that is for a mere handful of cornmeal to provide. If only all those excess calories in the American diet could be shipped postpaid to these reaches of Africa, the migratory bird routes, in trade for leaving the birds alone.

In central Wisconsin, we see nighthawks both coming and going. In the spring they follow the same thermal trades as trigger insect populations, to summer and mate in the fly-infested high arctic and the Canadian prairies. A domain somewhere north of Lake Superior, west of Moosejaw and James Bay. Unlike swallows nighthawks harvest insects at high altitude, often invisible even for bird watchers.

We were kayaking one evening, as is our custom, taking along a supper of sandwiches, a bottle of wine, cheese, carrots and dip and binoculars. This is among the most hallowed moments of the farm, a gentle submergence into my very own near wilderness.

On such a September evening, we were drifting at sunset, lounging, our heads back, looking to the sky, blame the wine if you want. As farmers we yet compete with that sailor’s claim of guessing the morrow’s weather by the clouds at sunset. Never mind a seven-day forecast is available on the cell phone, it is the more challenging to guess at the weather the old way, by reading the evening sky. Above us was a swarm of them, nighthawks, 30, maybe 40.

Seems they had struck an insect-buffet some two hundred feet over the stream and were diligently working it in the classic Spitfire feeding pattern.

This bird, the nighthawk, is a singular pleasure. The shape of their wings is enticing, their dark countenance, the white wing bar reminds every boy aviator of the invasion stripes on D-Day aircraft. The exotic angle of their sweepback wing seems designed for the dog-fight.

This sky dance lasted 20 minutes and then they or the insects moved beyond our horizon and were gone, and we were left with the realization it was quite dark and we yet a distance to go to our takeout, to stumble home in the dark.

Nighthawks are momentary things, they flow through the Wisconsin airspace in a span of a week, maybe two, then are gone. They are secretive birds, a short ephemeral treat for bird watchers. They adorn and tantalize the sky. They are quiet birds, they don’t gossip, they don’t boast, they pass as silent specters, to think they are Methodist.