An Urban Wildlife Mystery

One evening last spring, my friend Christopher and I sat on the sidewalk in front of my apartment building in Columbia. Traffic dwindled on the five-lane road in front of my house, and we admired the pink- and purple-streaked sky over the M.U. physics building across the street.I pointed to a dozen or so birds hovering high in the sky. Sometimes we lost sight of them, but usually we could see several at once hanging or ever-so slowly arching through the sky. They hovered until-with the gentlest tip of a wing-each bird began a wild and breathless dive. Wings tucked back, they plummeted headlong. In the moment before hitting the ground, they pulled up gracefully and leveled off, skimming parallel to the ground or sometimes along the rooftop of the physics building. Off they'd go again, rising higher and higher to start over. When it was too dark to see them anymore, Christopher told me a story.

A "Thump" in the Night

It was about 1 a.m. on a spring night four years ago; he had finished work and was on his way home. It was chilly out, and he was walking faster than usual. He heard an odd ruffling of leaves just as he passed beneath a Kentucky coffee tree, one of several planted in rows along some of Columbia's numbered, downtown streets. The ruffling escalated and he hesitated.

Something air-borne swooped out of the darkness and thwacked him on the back of the head-hard. It tussled for a second with his pony tail, then disappeared. Christopher lunged to a crouch and peered into the dark branches. Seeing or hearing nothing, he straightened up, ran his fingers gingerly through his pony tail and went home to bed.

On the very next night, it happened again. He was bewildered, a little spooked and extremely curious about what had attacked him. On the third night, he walked slowly but firmly, back straight, eyes wide open. He kept his pace steady as he approached the spot where the mysterious thing had clipped him.

Thwack! His head pitched forward, his pony tail swished, and he spun around, only to think he may have seen a flying creature whisk away to the darkness above the street lamps.

He went home and snipped off his pony tail with a pair of scissors, and tied off the new end with a rubber band from his desk. He attached the long hair to the front of a white fencing mask with a paper clip and stealthily made his way back to the spot. His lure was now attached to the front of his face where he could see it. He stepped onto the sidewalk and began to walk backwards.

He shuffled, stooped, bobbed, swung his head gently from side to side. Nothing. Nothing happened at all.

The Plot Thickens

Chris said he had no idea what exactly thwacked him those nights, though he was pretty sure it had been a bird, and it never happened again. We watched the birds hover and dive over the campus buildings across from my house a few more evenings that spring. We didn't learn the name of those birds either and, as the days grew muggier, we stopped sitting on my sidewalk and forgot all about them until late September.

We started playing tennis that fall and saw the birds again under the lights of a tennis court. The birds came swooping into our court, rising and swerving and darting in the cast of light. We soon realized the birds were expertly snatching moths that fluttered near our court lights. They made it appear easy, even though they gave chase with peculiar, irregular flappings of their wings, as if they had momentarily fallen into cadence with the erratic flight of the moths.

We counted about 12 birds that were shaped something like hawks. They had elegant white bands across the underside of each wing. We abandoned tennis and sat down to watch them feed. Surrounding us was a cluster of cold-looking, stone buildings and, beyond that, the rest of our small, noisy city. What kind of birds, we wondered, would find themselves here?

Determined Research

On the shelves of Ellis Library on the M.U. campus in Columbia, birds come after amphibians. The bird section begins with Acta Ornithologica, a Polish bird journal translated into English, and ends with a book titled Birds as Monitors of Environmental Change. In between them lie 32 feet of shelves holding books about the world's birds and every bird-thing you can think of.

Using an Audubon guide, I was able to identify the birds near my apartment and on the tennis court as common nighthawks. I learned they are related to about 16 caprimulgids or goatsucker species in North America, Central America and the Caribbean region. They are shaped similarly to hawks, but they are not birds of prey and do not have talons. They belong instead to the nightjar family and are related to whip-poor-wills and chuck-will's widows.

Common nighthawks have an unusual perch because they pitch forward on their breasts. That is why they sit long-ways on a power line. If they sat cross-ways, they would fall forward. Their legs are small and positioned somewhat awkwardly toward their tail ends. Consequently, they can't walk on the ground very well. Flying, as we witnessed from the tennis court, is their forté.

They migrate from South America and make their appearance in Missouri in late April and depart by late September. On the court, we saw them chasing down moths. To accomplish this, they are equipped with wide gaping, bristle-fringed bills that act as aerial sweepers, scooping insects on the fly. These facial bristles are specialized feathers and are only concentrated around their mouths. One book I read suggested they may function a little like cat whiskers, amplifying the sensation of touch. They may also serve as a sort of funnel, ushering more insects into the bird's open mouth.

The book also described their daredevil, downward plunges through the evening sky. It dawned on me those were nighthawks we had seen swooping over the physics building the previous spring. Only males make these plunges, and it's an effort to attract females for mating. As he comes searing down and abruptly levels off, his mouth and plumage catch the wind and make a thudding, windy noise. Females sometimes squeak when they fly, and males squeak repeatedly on the ascent. Once two birds have paired off, the male chases away any other courting males nearby and continues to perform celebratory loops, dives and swerves.

Nighthawk pairs don't build nests. Rather, they search for out-of-the-way rock surfaces, crevices in cliffs or a favorite urban nesting spot: gravel rooftops. Many buildings on the M.U. campus-including Ellis Library-have gravel roofs. Females lay two longish, somewhat elliptical eggs and arrange them pointy ends inward, which helps the adults cover them efficiently during incubation. They also cover the eggs with dusty-brown, downy feathers, which helps keep them camouflaged. Both males and females sit on the eggs and help feed the young after they hatch. Little ones learn to fly in about 21 days and linger near the nest. They raise their own young the next year.

Nighthawks belie their name. They often are around during the day, both perched and on the wing. At dusk they set out to catch insects-the only things they eat-but generally settle down after the sky goes black, making way for whip-poor-wills and owls.

And suddenly, Christopher's story came back to me. Could one of these birds have been the night time perpetrator that thwacked him in the head that cool spring evening?

Brad Jacobs, an ornithologist with the Conservation Department, listened politely as I recounted Chris' night time escapade with the spare hair and fencing mask. "It could have been a screech owl, maybe, going for the pony tail, but that's a long shot. An Eastern Kingbird might have done it, or a mockingbird. Mockingbirds and kingbirds will defend their territory. Was he near any bushes that may have held a nest?"

I said no, then ventured that perhaps he had been thwacked by a common nighthawk.

"It's possible," Jacobs said. "It could have been a common night-hawk, especially that time of year. They're back in Columbia by then." That was all I needed to hear.