I find the most nerve-wracking driving to be during that period of low light in early morning or early evening, the time when it is neither truly dark nor daylight. There is not sufficient natural light, and headlights are less effective. Twilight is one name for it, though we most often associate that term with evening. More inclusive is the scientist’s term, crepuscular, for a period that is neither day nor night, a time when darkness is approaching, or is departing.
It’s a time when I’ve had more than a few near-misses with deer on the rural roads I often drive, as well as a couple of actual collisions. Though some think of deer as nocturnal, they are most active in the times of fading light that leads to darkness, and the increasing light that leads to day. One particular stretch of lowland aspen, birch and alder, offers a high probability of encountering deer at these times, and the ever-present possibility that one will dart out into my path. Thus my anxiety, and my habit of staying below the legal speed limit here.
Another crepuscular creature is the owl, although there is no such thing as “the owl” in Minnesota. There are several owl species that are either year-round residents, or that visit us during seasonal shifts, generally in winter. Just this week, while driving through “deer alley” before sunrise on the way to work—on the lookout for roadside movement, with deer in mind—a shadowy blur arrowed across the road at treetop level.
The bird was in sight for only a few seconds, its wingbeats slowing as it pitched into a glide—broad wings spread—then disappeared into bare treetops beyond. A birder more serious than me might have known its identity, based on size, profile or perhaps wingbeat. Though I am keen on birds of all kinds—I have excellent binoculars, and a good bird book—I don’t have expert credentials.
By the process of elimination I concluded that it was an owl, having seen enough hawks to know that would be an unlikely ID. Wing size in proportion to body suggested this. In the same way that World War II fighter pilots could recognize enemy “bogies” by profile and size, by this bird’s profile “owl” seemed clear to me.
Timing was further evidence. While there are owls that hunt by day, the reverse—hawks that hunt by night—seems not to be the case. Hawks’ eyes are not exceptionally large because day hunters do not need the light-gathering power that night hunters do. Owl eyes, on the other hand, are said to be so disproportionately large that there is little room in their eye sockets for eye-movement musculature, requiring that they turn their heads to see in a different direction, rather than shifting the focus of their eyes only.
The larger eye mimics the principle that allows some camera lenses and binoculars to be used under very low light conditions. Larger lenses simply gather more light. Wildlife photographers carrying telephoto lenses approaching the size of a bazooka are doing this not to impress you, but to be able to capture images under low light conditions.
My best owl suspects, based on that brief overflight moment, were the great gray (we’re at the southern edge of its range), a great horned, a barred owl or a northern hawk owl. The snowy owl often slides down out of Canada in winter to hunt here, as well. The smaller Minnesota owls, like the long-eared, the northern saw-whet and the eastern screech owl, seemed unlikely choices, given the more massive body of the bird I had seen.
Of these larger varieties, the great gray seems least likely. With a body up to 30 inches in length, and a wingspread of four feet and more, these dimensions didn’t match the bird I had seen. The snowy and great horned owls are smaller than the great gray, but still on the upper end of the size scale. (Hedwig, a female snowy owl, is messenger and companion to Harry Potter in the book and film series.)
The best prospects seemed to be the barred owl, or the northern hawk owl. Their bodies—about 18 inches, give or take, and wingspan of two feet or slightly more—are a better match. The northern hawk owl is less common in Minnesota, and—like the snowy owl—is more often seen during winter, when it drops down from farther north to hunt here.
The northern hawk owl has a body shape and flight habit more hawk-like than other owls, thus the name. It also hunts during the day, as well as during periods of low light, and is not a true “night owl” hunter. I do remember that in that pre-dawn moment my brain formed the unspoken question: “Hawk or owl?” So I’ll go with that. Though less likely to be seen here in Minnesota—except at this season—I’ll cast my vote for the northern hawk owl, an unusual and beautiful example of that family.
No doubt it was about to take up its station in the top of a bare tree, there to wait for an ambush opportunity!