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February 17 - March 2, 2024
We think of owls as short legged because they tuck in their legs at rest and in flight. But most have long, well-muscled legs, up to half the length of their bodies, with strong bones, especially in their feet. Just before contact with their quarry, they thrust their powerful feet forward to strike, killing their prey with the force of the impact and crushing talons.
The facial disk in owls that hunt primarily by sound is outlined with a ruff, or ring of stiff interlocking feathers that capture sound waves and channel them toward the ears, like people cupping their hands around their ears.
An owl’s auditory system shares with other birds another superpower we mammals don’t possess: it doesn’t age.
A Great Gray Owl is listening, always listening. Its head rotates to glean the source of a sound. Its ears are so acutely tuned, it can discern the faint footfall of a shrew in the forest, the wingbeat of a Canada Jay, the muffled rustle of a vole tunneling deep beneath the snow. It will fly to the spot, hover over it, head facing down toward the sound, then just before impact thrust its legs forward and punch through snow more than a foot and a half deep to seize its prey.
The resulting auditory map allows owls to “see” the world in two dimensions with their ears.
However, having a narrow overall field of view has consequences. Stand near an owl, and it may bob and circle and weave its head from side to side, forward and back, up and down, sometimes torquing it until it’s nearly upside down. The bird is trying to get a good look at you.
Collectively, the serrated edge, the pennula, and the wispy tips unite each of the feathers into a single soft surface without sharp, noisy edges.
Why is quiet flight so vital to owls? Is it to avoid making noise that would interfere with an owl’s own hearing of its prey—what Clark calls the “owl ear” hypothesis? Or is to prevent prey, that cowering mouse, from hearing the owl’s approach—the “mouse ear” hypothesis?
Burrowing Owls can hardly be mistaken for any other species. They’re cartoonish, like a two-legged head, with long, almost stilt-like legs, a short tail, and a compact, expressive head that’s often cocked or turned in what looks like curiosity or an effort to get a different perspective. They’re funny to watch, natural clowns, with a habit of bobbing up and down when agitated,
Burrowing owl
A low-frequency hoot carries well and allows for maximum reach with minimum attenuation in a variety of habitats, assuming the hooting isn’t too close to the ground. When my friend Kinari Webb was studying orangutans in the rainforests of Borneo, she and her colleagues used owllike hoots to signal one another. “A medium-pitched whoo-whoo call carries well,” she says, so it’s the method most Indonesians use to locate one another in the forest. From the right perch, even the subtle hoot of the Long-eared Owl can travel more than a third of a mile, if wind or traffic doesn’t drown it out.
Low frequency hoot
By all accounts, monitoring these birds is extremely challenging. The species is nocturnal, difficult to spot because of its cryptic plumage and excellent camouflage, with little visible distinction between the sexes. Knowing the calls of individual birds is key to the task.
Time, patience, a musical ear: it’s a recipe for deep insight into how the owls use the valley; the boundaries of their territories and the posts from which males hoot at one another through the night; where they roost, hunt, build nests. And, of course, their population and their family life.
Courtship in owls is like this. No strutting around or flashing of splashy, colorful feathers, mostly just mutual hooting.
Courtship
A male will perch in a safe spot, back to a tree trunk, and call continuously through the night to advertise himself, 112 toots per minute, from a half hour after sunset to a half hour before sunrise. (David Johnson has timed them.) By morning, he’s hoarse. When a female comes into his territory, he’ll ratchet up the speed of the call to 260 toots per minute. Then he’ll show her his nest sites and give her a mouse to prove he’s a good provider. If his nest sites are up to snuff and his food offerings satisfy, she’ll stay with him. If not, she’ll fly off, and he’ll follow her, emphatically
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The Snowy Owl is the only owl species with distinct sexual dimorphism in its adult coloring and plumage patterning. In most owls, you can’t tell the sexes apart by their feathers.
Owls may be skilled hunters and mate finders, but skilled nest builders they are not.
Most owls don’t construct their own nests at all, but rather they appropriate structures built by other animals. The male usually finds a territory with abundant prey and some good nesting possibilities, but the female selects the actual nest sites.
Experts agree that we need a long-term conservation strategy to plan for and protect all the life stages of trees, from cavity-bearing live trees to snags and woody debris, so that there is a continuous supply of nesting habitat in forests around the globe.
Females can’t afford the risk of diminishing food supply in winter, so they seek a warm, safe place to fuel up before they breed again. Males want to stay where they have quicker access to the best territories in the spring. So they move in the winter, but they move laterally, shifting around looking for places with a big rodent population.
The questions abound, but one thing seems clear: these owls know what they’re doing, and their decision to stay or to go, to tough it out in a place or to seek new ground, is part of a complex calculus we don’t yet fully understand.
But owls? The knock on owls is that most of the cortex-like part of their brains is dedicated to vision and hearing, some 75 percent, in fact, which supposedly leaves only a quarter for other purposes.
“We used to talk about how owls weren’t intelligent,” she says. “They just had all these great adaptations for survival and didn’t really need to have a lot of smarts. They were acting pretty much only from instinct rather than from learning. But I’ve made a complete one-eighty from this, totally changed my mind. Owls certainly hatch with a lot of the tools they need, but they learn throughout their whole lives. Their survival depends on it.
The capacity to make flexible decisions over a lifetime, to learn, shift strategies, explore, and adapt—in the case of urban Burrowing Owls, in a remarkably short period of time—certainly qualifies as a kind of intelligence.
It seems to me that owls are showing us how birds can embody intelligence, in their eyes and ears, their cryptic coloring and flight, their memory and hunting skill, their flexibility, nuance, creativity, and discernment.
The wide-ranging generalists of the owl world, the Barred Owls, Ural Owls, and Eastern Screech Owls, seem to be doing well, expanding their populations. These birds with flexible diets and habits will try almost anything to make a living, and can thrive even in dense and chaotic urban environments. Their adaptability and ingenuity at making use of the human-shaped world might be viewed as a positive sign.
Others, such as Little Owls, Northern Saw-whet Owls, and Great Horned Owls, are holding their own in the face of change. But many owl species are at risk from the disappearance of the big old-growth trees that once harbored their nesting hollows and the vast meadows and grasslands that served as their hunting grounds, from the threat of invasive species and rodenticides, and from the widespread effects of climate change.
