Hawk and Owl
The Seen and the Unseen
Better not get too close.” Claire and I were out on an autumn stroll in the neighborhood, and this advice was proffered by a round, baseball-hatted gentleman, arms folded atop his belly. “It’s a red-tailed hawk, and it’s got a pigeon,” he reported, nodding toward the sidewalk. “No telling what it will do.” We spotted the birds on the grassy parking strip, a Cooper’s hawk with a lifeless pigeon beneath his bright yellow feet. Claire looked at me sidelong with big, slightly anxious eyes. She was not worried a whit about a hawk attack, but she’d heard my Why-is-it-that-the-only-hawk-name-people-know-is-the-red-tailed-so-they-call-anything-resembling-a-hawk-a-red-tailed speech often enough to know that the innocent group of five or so folk that were gathering around this unfolding urban-wild drama might be in for a lecture. I winked at her and held my tongue. I loved this misguided but well-intended advice, spoken with such authority—the worry that this little hawk, overcome with possessiveness over its pigeon, might attack a human. An elderly couple now came out of their house, smoking, and the “Stay back” guy, who, with his posture and substance, had taken charge of the situation, kept yelling “Shut up!” at the barking retriever tied up on his porch. Crows dive-bombed the hawk mercilessly, and more were coming in—a couple dozen of them. The thin young Cooper’s could almost speak with his eyes: Oh, please, please, just leave me alone, just let me have my pigeon. But it was too much for him—humans, retrievers, cigarettes, crows—and he finally fled sans pigeon (a heavy bird for a Cooper’s to carry in flight) to a high branch in the near birch. He was wild-eyed and fearful now, turning from the dog to the onlookers to the crows, straggles of downy pigeon feathers hanging from his bill and feet. We stood together, none of us, including the hawk, ready to give up the moment. I was about to suggest that we quietly leave, let the bird have his meal, but then I gasped, along with the rest of the human onlookers, all of us unprepared for what happened next. The still cloud of feathers in the grass that was the dead pigeon burst into flight and was gone.
Which Hawk?
In the Aberdeen Bestiary, there are two kinds of hawks: wild and domesticated. Domesticated birds would have been falcons or accipiters whose legs were fitted with leather jesses held by the falconer’s hand. The lack of further differentiation is singular. In the urban wilds, many species of the various hawk tribes are possible—v-winged falcons, eagles, the fish-eating ospreys, soaring buteos, and forest accipiters. Of these, Cooper’s, sharp-shinned, and red-tailed occur in most neighborhoods.
Cooper’s and sharp-shinned hawks are stunning bird-eating hawks that regularly grace the urban wilds, visiting our gardens and perching near our feeders, preying on passerine birds. They are not common in terms of numbers, but individual birds turn up consistently and dramatically. Both belong to the accipiter tribe—long-tailed birds with shorter wings for navigating forest corridors in pursuit of smaller birds. These little hawks fling themselves from trees and into the air with thrilling abandon. Adults of both species have blue-gray backs, darker gray heads, buff and orange breasts, orange-red eyes, and long yellow legs. Younger birds remain streaky brown with yellow eyes until they are about two years old. Both sometimes make a sweet, quizzical expression. While Cooper’s are generally larger, size is difficult to judge in the field. Female raptors of all species, both hawks and owls, are substantially larger than males, but this is especially true of the sharp-shinned hawk, where females are up to 57 percent larger than males. This means that a large female sharp-shinned might be bigger than a small male Cooper’s. Even so, if you see one of these hawks alongside a crow (which is where you typically see them, as crows come in to chase a hawk away the second they spot one), you can make a good guess as to which hawk you are looking at—the body of a sharp-shinned hawk is decidedly smaller than a crow, about the size of a robin (they look bigger, because their tails are so long and their heads are larger, and maybe also because they are so aggressive). A Cooper’s hawk’s body is about crow-size.
Red-tailed hawks are common urban raptors in the buteo tribe—soaring birds with nicely proportioned wings and fanning tails. Perched on branches or highway lampposts, red-tails are shaped just like footballs and are shades of brown, with a buff-ivory breast, typically with a necklace of brown feathers across the belly. In flight, the red of the tail shows through, though young birds will have brown-striped tails until they are about three. Unlike the accipiters, red-tails are not fussy about their diet, one of the things that make them the most ubiquitous raptor in North America. They eat snakes, lizards, mice, rats, rabbits, chipmunks, squirrels, opossums, smaller skunks and young raccoons, ducks and any other birds they can manage to catch (buteos are not as speedy or agile as accipiters and falcons), grasshoppers, cockroaches, even butterflies. They will eat domestic pets, particularly cats, but also puppies or smaller dogs. A fat little backyard chicken is just right for a red-tail.
There is much to entice a raptor in the city—structural complexity (built, if not botanical), abundant prey in a concentrated place (rats, mice, pigeons, huge flocks of starlings, grasshoppers, cockroaches), water sources, and moderate temperatures (with their heated buildings, most cities run several degrees warmer than neighboring rural places). Birds of prey lace our cities—the edges, parks, cemeteries, and backyards. Red-tails roost on highway corridor lampposts, where snakes, rats, rabbits, and mice populate the grassy medians; bird-eating sharp-shinned and Cooper’s hawks dart through our yards or perch stealthily in our garden trees, waiting for a chance to snatch a sparrow or starling meal from our feeders; peregrine falcons nest on skyscrapers and bridges, feasting on pigeons. In watery places, ospreys, like the peregrines recovering from plummeting populations before the banning of DDT, respond favorably to nesting platforms and make themselves at home in urban parks. A merlin flew overhead during my neighborhood walk the other day, a small falcon whose uncommon presence warranted a call to my birder neighbors. And though owls in general are not known for their love of bathing, in the secret darkness, screech owls splash in our suburban birdbaths, snatching a moth or mouse on the way back to their roosts. Great horned owls roost in the largest trees at a city’s leafy edges eating rats, skunks, and cats and calling, hooting, dueting with their mates all night long and into the Yeatsian dawn.
Some researchers believe that urban environments exist as an ecological sink for many raptors, that is, as a poorer-quality habitat in which the population could not be self-sustaining without an influx of birds from a higher-quality habitat. Most raptors that nest in cities suffer far less depredation upon their nestlings than raptors that nest in rural places—probably because in the watered-down urban ecosystem, there are fewer predators to eat them. But there are unique urban hazards that may balance out, or even offset, this benefit: electrocution, malnourishment, illness from eating diseased birds who have picked up infections at ill-kept feeders, disturbance by human presence causing nest abandonment, and, more than all of these, cars. One study of Cooper’s hawks indicates that birds that become accustomed to humans when young don’t live as long as others, for reasons yet unknown.
Both hawks and owls are present in far fewer numbers than most other avian species that populate urban areas; as carnivorous predators, they are at the top of the food chain. Just as there are more squirrels than coyotes, there are more robins than red-tails. Though there are fewer of them, these birds somehow take up a greater quantity of our psychic space and inspire disproportionate excitement when seen, capturing our imaginations and our hearts. The red-tail Pale Male and his various mates in Manhattan were made famous nationwide by the book Red-Tails in Love, and when the hotel they nested on decided it was done with the whitewash mess flung down its stone sides, public outcry kept its owners from removing the nest, and Pale Male claimed a full front-page spread in the New York Times, with an illustrated genealogy of his mates and descendants. Here in Seattle we had the peregrines Stuart and Belle nesting famously on the Washington Mutual
Bank–cum–Chase Tower, spectacularly dispatching pigeons, raising their black-eyed chicks, and starring in a beautifully photographed children’s book. We fix owl-cams, eagle-cams, hawk-cams upon their nests and spy at all hours on the busy engaged parents, the fluffy, playful, vulnerable young.
This heightened attention to raptors has surfaced in all cultures over the course of history, always and everywhere. The presence of a raptor is meaningful. We catch them at the edge of our peripheral vision, our own animal viscera responding instinctively to the shadow of a predator spiraling overhead.* These are birds that fly between the worlds of life and death and then, with a silent, unexpected rush, they bring these worlds crashing together. There are other birds, the avian scavengers—crows, ravens, vultures—whose biology draws them into real and symbolic association with death. But our response to scavenging is very different from our response to the capture of prey. The awareness of death called up at the sight of a hawk or owl is fresh, careening, near. If we chance to see a raptor with its prey, the victim is so new, so suddenly dead. This death is no flattened roadside opossum; it’s visceral, pressing, the victim so recently alive that we can feel it living still, must look twice to be sure, and even then cannot help but wonder with a hopeful, irrational compassion rising unbidden from a shared biological frailty: Did I see it move? Might it still live?
It is rare to see a raptor actually catch its prey; birds of prey are fast, secretive, stealthy, eat only once or twice a day, and, in the case of most owls, hunt in the dark night when we are tucked in and dreaming. But we can sense the possibility—the immediacy of a hunt—in their physiology, in every turn of sinew and feather, made for this preying. The rich cross-cultural mythology surrounding these birds rises, as all good myth does, straight from their bodies, their hunt-and-kill-adapted physiology. Regarding the red-tailed hawk on the highway lamppost, the great horned and screech owls on our city edges, we see that Darwin’s truth (adaptations of eye, talon, feather, piercing bill) and the insights of ancient myth (from Egypt to the North American plains, where hawks and owls are spiritual conduits from life to death) meet and blend.
Biologically, the two groups are not closely related. Hawks and owls share physical adaptations like big brains, clutching feet, curling talons, and binocular vision as a function of convergent evolution—they both have similar physical/lifestyle requirements, resulting in separate lineages evolving similar traits. (Convergent evolution regularly crosses larger biological gaps than the span between owls and hawks—flippers in both penguins and dolphins, for example, or dorsal fins in porpoises and sharks, or long sticky tongues in woodpeckers and armadillos.) But it makes sense that hawks and owls are entwined in both our psychic and ecological landscapes. Mythologically, these birds have always evoked power, vision, wisdom, the hunt, transition, death. Hawks represent the solar aspect of these themes, owls the lunar. Most large predatory animals claim an absolute spatial territory, but for hawks and owls, there is a temporal dimension as well. They hunt in the same place and share a similar prey base, but they are separated by time and light, with some species in particular forming layered, territorial pairs. Red-tailed hawks and great horned owls are linked in this solar/lunar way, as are, sometimes, the small falcons (kestrels and merlins) and screech owls. There is a bit of safety in this arrangement, as the individual birds and their territories are afforded some protection by the vigilance of the one predator while the other is asleep. Unless we are trying hard, we see more hawks than owls, so I love to keep this eco-poetical truth in mind: When a hawk shows herself beneath the light of the sun, somewhere nearby her lunar owl sister sits, bark-plumage invisible against the trunk of a park tree, feathered lids closed against the intrusive daylight. The seen and the unseen, equally real and present among us.
Most owls are not the least inclined to build nests. They prefer to purloin the nests that others have made and touch them up a very little bit, if at all. Smaller owls, like the common urban screech owls, nest in small cavities made by woodpeckers, found in natural hollows, or provided by nest boxes. If other birds are already in the hole, they will chase them away, cover their eggs with grasses, and blithely lay their own clutch on top of them. Large owls will take over the used stick nests of hawks, and great horned owls in particular are known for happily reusing the old nests of their daytime counterpart, the red-tailed hawk. And while the red-tails somehow leave perfectly serviceable nests behind after fledging their young, when the owls and their big-footed, trampling chicks are done with it, nothing will be left but tatters, a nest beyond repair.
To find owls, dream and hope.* To find hawks, look up. Seeing a raptor is always a thrill. But in daily urban life, it happens as often by chance, happenstance, or luck as by effort or desire. Unless you have been studying a place with some consistency, finding a hawk at will or whim is an uncertain endeavor. Nearly all of my urban hawk sightings occur in the moments I happen to look up—from my writing, my coffee, my navel—and there will be a sharp-shinned, shooting flat across the yard, a kettle of vultures rising on a late-morning thermal, a red-tail circling high. Some study and watching, developing a sense of what to look for, learning to discern a raptor from the ranks of the crows and ducks and robins—all of this will help, as will a readiness to see. I always find that if I am in a raptor-study mood—reading up on the latest research, studying taxonomy or identification secrets, or just thinking about hawks on a given day—I will see more of them. Always. It is a spiritual/psychological corollary, one that I cannot explain but that is absolutely true. Quiet expectation, along with experience and luck, all help in the finding and observation of any wild animal.
Raptor Brains, Bird Necks, and the Trouble with Owl Eyes
Raptors look smart because they are. The brains of both hawks and owls are proportionately large, as birds go, in part because survival by aerial hunting requires a scrappy plasticity of behavior and the intelligence that accompanies it. The consciousness of hawks and owls has been little studied, but, like crows, ravens, and parrots, both owls and hawks appear to play, a category of behavior associated with high intelligence. Red-tails drop sticks and catch them on the wing, just as crows and ravens do. Accipiters appear to fly more often on windy days, enjoying aerial acrobatics for no good, “practical” reason. Fledgling owls of various species, including the western screech, have been observed pouncing on inanimate objects or dead prey very much like kittens. And my physician friend Bob called one morning to report that a great horned owl in a nearby park had chased the yellow tennis ball he threw over and over for his big dog, Molly. The owl would swoop over dog and ball and then lift at the last minute, letting the dog catch her toy. With her precise vision, it was unlikely she mistook the ball for prey. The question of play among the raptors is a relatively new one. The truth is, we don’t know, and we likely underestimate, the breadth of their interior lives, as is true for our knowledge of most nonhuman animals, including, as Darwin showed us, earthworms.
Owls cannot turn their heads all the way around, as is commonly believed, but they can rotate their heads 270 degrees in either direction. Owls have fourteen cervical vertebrae, twice as many neck bones as humans possess (and with seven cervical vertebrae, we can turn our heads only eighty to one hundred degrees without injury), but not that many for a bird; even the shortest-necked birds have eleven cervical vertebrae, and longer-necked birds like grebes or geese have up to twenty-five, which gives them all a good range of motion in the neck. And in all birds, including owls, the large carotid artery runs along the middle of the neck vertebrae, rather than alongside them as it does in humans. This keeps the artery from being pinched and damaged during rotation, allowing even more cervical mobility. So why don’t we see all the birds contorting their necks in that trademark owl fashion? Well, what is unique to owls is the need to turn their heads so far, a need that has as much to do with their brains and eyes as it does their skeletons.
An owl’s skull must fulfill many competing requirements. It must pro
vide space for a brain big enough to accommodate the intelligence and versatility of behavior required by a successful predator; have room for eyes large enough to be keen in the night; maintain a structure that sits proportionally atop the bird, not becoming too top heavy; and remain light enough for the bird’s agile flight. In all of this, an evolutionary compromise has been wrought. With the owl’s big brain and sharp eyes squeezed into the skull, there is no room for anything else, not even a bit of space around the eyeballs. There is some variation among species, but in general the owl eyes we see looking out at the world in that startling owl way are fit so snugly within their sockets that they cannot move. Owls have to turn their heads, sometimes dramatically, in order to see anything other than what’s straight ahead of them. Though other birds might have the flexibility for extreme neck rotation, most of them cannot pull it off too often or for too long without injury.
New research published by an interdisciplinary team at Johns Hopkins finally explains the mystery of how owls are able to turn their heads so far, so frequently, and for such extended periods of time without damaging their arteries, or cutting off the blood supply to their brains and having owl strokes. To conduct the study, the researchers infused an x-ray enhancing dye into the cervical blood vessels of dead barred, snowy, and great horned owls (all had died of natural causes). Imaging the owl’s necks during movement, they were able to discern that the holes in owl neck bones through which major arteries travel are much bigger than they are in other birds, and they are buffered with air sacs; the space and the cushioning protect the arteries during rotation. In addition, the blood vessels nearest the head and jaw are expandable—they can fill with reservoirs of pooled blood. These little balloons of blood supply the owl’s brain during extreme movement. “There’s no real clinical relevance here,” quipped one of the scientists, “other than don’t try this at home.” But it’s wonderful that in this age of techno-science, there are still basic physiological secrets to be told by the creatures we thought we knew best.
The Urban Bestiary Page 21