With the distinctive forward-facing gaze that can make
owls seem as much human as bird, the barred pair stared at me. I played the call
again, the male grew bored, and I was about to put the phone away when suddenly
the female — the larger of the two owls, as female birds of prey often are —
pitched her body forward on her perch, lifted up her heavy, magnificent wings
and belted out a full-throated retort to my recorded call.
After a brief pause, she hooted the eight-note
sequence once more, at which point an astonished zoo-goer nearby burst into
applause. In the Western imagination, the owl surely vies with
the penguin for the position of My Favorite Bird. “Everyone loves owls,” said
David J.
Bohaska, a paleobiologist at the Smithsonian’s National Museum of Natural
History, who discovered one of the earliest owl fossils. “Even mammalogists love
owls.”
Owls are a staple of children’s books and cultural
kitsch — here wooing pussycats in pea-green boats and delivering mail to the
Harry
Potter crew, there raising a dubiously Wise eyebrow in the service of snack
food. Yet for all this apparent familiarity, only lately have scientists begun
to understand the birds in any detail, and to puzzle out the subtleties of
behavior, biology and sensory prowess that set them apart from all other avian
tribes.
Researchers have discovered, for example, that young
barn owls can be impressively generous toward one another, regularly donating
portions of their food to smaller, hungrier siblings — a display of altruism
that is thought to be rare among nonhuman animals, and one that many a small
human sibling might envy.
The scientists also discovered that barn owls express
their needs and desires to each other through a complex, rule-based series of
calls, trills, barks and hoots, a language the researchers are now seeking to
decipher.
“They talk all night long and make a huge noise,” said
Alexandre Roulin of the University of Lausanne, who recently
reported
on barn owl altruism in the journal Animal Behaviour with his colleague
Charlene A. Ruppli, and Arnaud Da Silva of the University of Burgundy. “We would
never put our nest boxes in front of a farmer’s bedroom, or the person wouldn’t
be able to sleep.”
Other researchers are tracking the lives of some of
the rarer and more outlandishly proportioned owls, like the endangered
Blakiston’s fish owl of Eurasia. Nearly a yard high, weighing up to 10 pounds
and with a wingspan of six feet, Blakiston’s is the world’s largest owl, a bird
so hulking it’s often mistaken for other things, according to Jonathan Slaght of
the Wildlife Conservation Society’s Russia program. It could easily look like a
bear in a tree or a man on a bridge.
Or maybe Ernest Hemingway. This powerful predator can
pull from the river an adult salmon two, three or more times its own weight,
sometimes grabbing onto a tree root with one talon to help make the haul.
Ferocity is essential for a bird whose frigid, spotty
range extends across northeastern China, the Russian Far East and up toward the
Arctic Circle, one that breeds and nests in the dead of winter, perched atop a
giant cottonwood or elm tree, out in the open, in temperatures 30 degrees below
zero Fahrenheit. Dr. Slaght’s colleague Sergei Surmach videotaped a female
sitting on her nest during a blizzard. “All you could see at the end was her
tail jutting out,” Dr. Slaght said.
Researchers have discovered, for example, that young barn owls can be impressively generous toward one another, regularly donating portions of their food to smaller, hungrier siblings — a display of altruism that is thought to be rare among nonhuman animals, and one that many a small human sibling might envy.
Owls are admired for their ability to fly through the night silently in pursuit of a meal.
Researchers have traced that silent flight to several
features. The bulk of the wing is broad and curved — the ideal shape for slow
gliding — and is abundantly veined with velvety down plumage to help absorb
sound. Moreover, the feathers at the edge of the wing are serrated to
effectively break up and smooth out air turbulence as a comb disentangles knots.
At a meeting of the American Physical Society last fall, researchers from
Cambridge University
proposed that
well-placed perforations in an airplane wing could have a similar smoothing
effect on turbulence, leading to quieter and more fuel efficient flights
Owls date back 60 million years or longer, and they’re
found in nearly every type of habitat: tropical, tundra, desert, Central Park.
Some 229 species are known, and the list keeps growing: last summer, two new
species of hawk owl were discovered in the Philippines, and earlier this month
researchers reported on a new species of screech-like owl from the island of
Lombok, Indonesia.
The birds own the night, although some hunt at dusk
and dawn and even during the day. And hunt owls tirelessly do. By one estimate,
a group, or “parliament,” of 10 owl families living in a barn in Central Florida
cleared the surrounding sugarcane fields of about 25,000 cotton rats a year.
Owls were long thought to be closely related to birds
of prey like hawks and eagles, which they sometimes superficially resemble —
hence the names hawk owls and eagle owls. But similarities of beak or talon turn
out to be the result of evolutionary convergence on optimal meat-eating
equipment, and recent genetic analysis links the owls to other nocturnal birds,
like nightjars.
Through the Global Owl Project, Mr. Johnson is working
with researchers in 65 countries to compile a vast database and celebration of
all the world’s owls, with descriptions, natural history, genetics,
vocalizations, rough population estimates, owl myths and legends.
Westerners love owls, he said, a tradition that dates
back at least to the ancient Greeks and the association of owls with the wise
goddess, Athena, and her gray “shining eyes.” In some countries, though, owls
are seen as bad omens and harbingers of death — perhaps, Mr. Johnson proposed,
because owls often nest in cemeteries, where trees are left to grow undisturbed
and the nesting cavities are comfortably large.
Would that owls might lend us their ears. Species like
the barn, barred, screech and horned have some of the keenest auditory systems
known, able to hear potential prey stirring deep under leaves, snow or grass,
identify the rodent species and even assess its relative plumpness or state of
pregnancy, based on sound alone.
Again scientists attribute that to a consortium of
traits. Prof. Tim Birkhead of the University of Sheffield points out in his new
book, “Bird Sense,” that the owl cochlea is “enormous” and densely packed with
sensory cilia. The barn owl, for example, has three times the number of hair
cells expected for its body size. The paired ear openings are also exceptionally
large and asymmetrically placed on either side of the skull, the better to help
localize a sound’s origin; the super-swively neck further enhances the power to
sample the ambient soundscape.
Then there is the owl’s famously flat face, also
called the facial disk — pie-shaped in some species, heart-shaped Kabuki in the
barn owl. The facial disk serves as a kind of satellite dish, to gather sound
waves, which are then directed to the owl’s ears by stiff, specialized feathers
along the disk circumference.
Even the owl’s forward-facing eyes may have as much to
do with hearing as with vision.
Graham
Martin of the University of Birmingham has proposed that with so much of the
lateral real estate on the owl’s skull taken up by the giant ear openings, the
only place left to position its eyes is in the middle of the face.
Here’s looking at you, Strix. Will you please call
again?
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