Tyger Tyger, burning bright,
In the forests of the night;
What immortal hand or eye,
Could frame thy fearful symmetry?
In what distant deeps or skies.
Burnt the fire of thine eyes?
On what wings dare he aspire?
What the hand, dare seize the fire?
~William Blake, "The Tyger" from Songs of Innocence (1892)
By George Ellison with illustration by Elizabeth Ellison
Those wonderful opening lines of "The Tyger" were written after William Blake had seen the real thing at one of the numerous traveling circuses that passed through London each year. But they could have been written about the Great Horned Owl, that fabulous bird that roams North American forests at night and is sometimes referred to, without exaggeration, as “The Tiger of the Night.”
Standing more than two feet tall, with a wingspan of four and a half feet and talons that can rip though a fencing mask, the Great Horned will hunt by day, but it is supremely equipped for night stalking.
The feathered tufts ("horns") on the top its head resemble ears but aren't. The real ears are slits hidden among the feathers on the side of the head. Placed asymmetrically, these admit slightly different frequencies to each eardrum, enabling the bird to pinpoint the origin of faint sounds.
Its eyes are 35 times more sensitive than those of a human, so that, in a test situation, a Great Horned was able to capture prey in light so dim it was the equivalent of a candle burning in the dark nearly half a mile away.
Specialized wing feathers, downy-fringed like a butterfly's, enable this predator to move silently in flight. No sound of rushing wings warns the targeted prey of an incoming strike of devastating velocity.
Part of its strategy for survival, the Great Horned breeds and lays eggs in the depths of winter. Chicks appear in very early spring, are blind and helpless, and require full parental care for many weeks. The winter breeding strategy will now pay dividends, for hunting is easier without thick foliage on the trees and the Great Horned Owls are unsurpassed when it comes to locating and dispatching prey.
Small birds are the preferred food for owlets, but a mature Great Horned Owl can and does feed upon most of the animals it encounters, especially birds, rabbits, and rodents. Those who have studied the Great Horned closely report that they have a poor sense of smell and thereby have been able to make skunk one of their favorite foods.
The Great Horned can bark, grunt, shriek, and yelp, but the call you'll most likely identify is a quick cadence of five or six low hoots—"whoo hoo, hoo, whoo, whoo”—delivered by the male or the female's seven or eight hoots given at a lower pitch.
For Elizabeth and me, it's impossible not to agree with Thoreau—who observed the natural world at his doorstep with such loving scrutiny—that the calls of the Great Horned Owl “occupy the spaces rightfully” as if made by the “twilight woods” themselves, and, in doing so, signify a “vast undeveloped nature which men have not yet recognized nor satisfied.”