Birding: Easily heard, but seldom seen birds of the night

Aristotle wrote about the avian family to which whippoorwills belong, although he got it wrong. Ornithology was in its pre-infancy in ancient Greece, and science and folk tales often were lumped together.

He was questioning shepherds about stories of birds sucking milk from the udders of goats. Not true, as it turned out. But the name goatsucker had legs. Today, the avian family to which whippoorwills belong is called goatsucker.

The birds of the family also are known as nightjars. My rural granny would have raised her eyebrows had she heard that.

That name as it applies to this large, worldwide family of birds is said to come from the sudden, loud — jarring — night calls these birds can make.

Minnesota has one nesting member of this family, the whippoorwill. Like many of its relatives, it says its name, repeatedly, once per second, romantic from a distance, annoying when just outside the cabin window.

Its scientific name is Caprimulgus vociferus. The first part is derived from the Latin word for goat milker. The second accurately refers to its voice.

If whippoorwills are in your woodland neighborhood, they are easy to hear. Their calls mark dusk and dawn, active time for these birds. They are insect hunters, hawking from a perch to grab prey.

The best way to see one is to drive along rural roads just after dark, watching ahead for the red glow of the birds' eyes. The species has the habit of sitting on roads.

That's how grandson Cole and I got our first close look at a whippoorwill last summer at Crex Meadows Wildlife Area near Grantsburg, Wis. We saw its eyes a second late, or did the bird rise from the road a second late? At any rate, we ran over it.

Unfortunate, certainly, with the benefit, however, of close examination for us. Snatching insects out of the air is an uncertain way to make a living. Whippoorwills, like fellow tribe members, have huge, gaping mouths.

When they are at rest, you see the small, neat end of the closed bill, quite bird-like. In action, the mouth is the maw of a predator, looking wide enough for the bird to swallow its own head. To locate flying insects, the bird has long, stiff whiskers at each mouth corner. These might also help funnel prey into the mouth.

Because of its camouflage and night habits, we know surprisingly little about this species. We know that whippoorwills will use nights of the full moon to hunt while flying instead of from a perch. Better light, better results. We know that young whippoorwills are very precocious birds, able to fly when just 10 days old.

Calvin Cink, writing about whippoorwills in 2002 for "The Birds of North America" monograph series, said much of what we know about the species is anecdotal. Formal studies have been few. The phrases "little information, no information, poorly known, and not well studied" are sprinkled liberally through his paper.

To a large degree we still rely on anecdotes. Aristotle would understand.

Lifelong birder Jim Williams can be reached at woodduck38@gmail.com. Join his conversation about birds at www.startribune.com/wingnut.