Page 24 - Abacoa Community News November '23

Page 24, Abacoa
Book Review

What An Owl Knows: The New as the only bird whose “While it’s a myth that owls can rotate their heads from
Science Of The World’s Most big round eyes face a starting point facing forward, some species, like Great
forward, like ours, in
Grays and Barn Owls, can turn their heads almost three
Enigmatic Birds the front of their faces. quarters of the way around, 270 degrees – three times the
All other birds’ eyes twisting flexibility humans possess … that an owl’s neck
By Nils A. Shapiro are situated on the sides can move swiftly and smoothly through those 270 degrees
Au t h o r Je n ni f e r of their heads. of rotation is due to some clever adaptations, a loose S
Ackerman could just as But unl ike we shape that gives it flexibility, and a system of bones and
well have retitled her humans, who can move blood vessels that minimizes disruption of blood flow
book What We Know our eyes left and right through the neck to the eye and the brain when the head
About Owls, packed as it with a limited degree rotates.”
is with many hundreds of of peripheral vision And I haven’t even touched upon an owl’s vision, with
fascinating facts about the in order to see what is its ultraviolet spectrum.
260 owl species to be found happening on each side There is so much more here to enjoy, and from which
throughout almost every of us, an owl’s eyes are to learn. Plus 50 black-and-white photos and a section
continent, from the tiny elf fixed facing forward. of full-color photos that add greatly in helping you to
owl, the size of a pine cone However, they make identify different owl species.
only a few inches high, to the massive Eurasian eagle- up for that by being able to swivel their heads around in
owl that can take down a deer – or Blakiston’s fish owl, a way that we cannot:
the world’s biggest owl, the size of a fire hydrant with a
6-foot wingspan!
The recipient of numerous awards and fellowships
and author of five earlier successful books – including
The Bird Way and national bestseller The Genius of Birds
– Ackerman’s own awe and appreciation for the skills
and natural physical attributes that these extraordinary
creatures have evolved over the 100 million years since
they have existed on this planet is clear from first page
to last. The following brief passages serve as examples,
some of the text has been omitted for lack of space here,
and been replaced by ellipses (…):
“With a head designed for listening … the flat, gray
head disk of a Great Gray Owl is like one huge external
ear, a feathered satellite dish for collecting sound … The
facial disk in owls that hunt primarily by sound is outlined
with a ruff of stiff interlocking feathers that capture sound
waves and channel them toward the ears, like people
cupping their hands around their ears. Feathers in the
back of the disk direct high-pitched sounds toward the
ears, so the owl hears less noise from its surroundings
and can focus on prey cues.
“(The owl) can even change the shape of the disk by
using muscles at the base of the feathers, shifting from
a resting state to the alertness of an active hunt. It’s
remarkable to watch an owl do this, adjust its facial disk
when it hears something interesting. It’s like the disk itself
is a kind of aperture, an ‘eye,’ that opens wide to let in
more sound and bounce it toward the ears.”
Note: The use of the term “ears,” in owls, even in such
species names as long-eared owls or short-eared owls, is
confusing. The actual ears used by owls for listening are
vertical slits on the sides of their heads.
Owls are nocturnal, hunting at night for prey that
includes most commonly – depending on the owl species
and size – rodents, insects, mice, rabbits, squirrels,
possums, lemmings in the case of snowy owls, and other
small mammals and birds. Because of their incredible
hearing, and the fact that the unique design of their wings
enables them to swoop down on prey in complete silence,
they are among the natural world’s most efficient hunters.
They do not even have to be able to see their prey in order
to be successful!
“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.”
But Ackerman has equal respect for the professional
scientists, students and volunteers who often dedicate
years of their lives under the most incredibly difficult
physical and stressful conditions worldwide, studying
every aspect of owls’ lives in order to build the base
of knowledge that will help protect the survival of owl
species at a time when many are at risk of extinction due
to climate change and other human influences.
One chapter, Who Gives a Hoot, includes the
experiences of researcher Karla Bloem, who devoted
an extensive amount of time studying variations in owl
language at just one site:
“After hundreds of hours of meticulous observation,
Bloem managed to characterize and describe fifteen
separate vocalizations: six sorts of hoots, four types of
chitters, and five kinds of squawks, including an alarm
squawk like an eerie shriek. She also noted that the owls
have nonvocal communication. When they’re fearful or
agitated, they’ll hiss or clack their bills.”
Perhaps the major reason why owls are so popular
worldwide is their most instantly recognizable feature