Let me tell you a little something about
how birds fall asleep. Maybe we both
could grab a tasty little birdie treat
with this information.
More than half of bird species are perching birds
(known as passerines or songbirds). This includes about 5,500 species,
including wrens, finches, sparrows, orioles, cardinals, starlings, and many others.
Part of what makes perching birds so fascinating is their ability to sing a
song unique to their species. Some perching birds are born knowing
their song while others actually learn them from their parents.
Equally intriguing, however, is the makeup of a perching bird’s feet.
Aside from having the ability to fly, having feet that can grasp onto
branches, reeds, grasses and even sheer cliffs and tree trunks is
one of their best defenses against predators.
Contrary to popular belief, these birds do not sleep in their nests
(which are reserved for laying eggs and raising chicks).
Instead, they sleep (or roost) safely tucked away in
dense vegetation, including trees and shrubs.
At dusk, a perching bird will choose a spot to roost for the night,
often burying its bill and one leg up into its feathers.
It will then roost comfortably in that spot until dawn, which makes
many people wonder how they’re able to maintain such a pose without falling…
Perching Birds Can’t Help But Perch
Perching birds’ feet are quite literally made to perch.
Each foot has four toes, three that face forward and one that faces
backward (technically this is called an “anisodactyl arrangement”).
While each toe moves independently, the backward facing toe is extremely
strong, helping ensure a strong grip.
Even more importantly, perching birds have flexor tendons
in their legs that force their toes to involuntarily clasp on a perch
as soon as their ankles bend and their body weight presses down,
sometimes referred to as a “stay mechanism.” Only when their
legs straighten will the tight clasp be broken, so a sleeping bird
cannot physically “fall” from a branch.
Where Do Non-Perching Birds Sleep?
Not all birds have this same ability to grasp branches.
Some birds, like geese and ducks, have webbed feet, which makes
them well-suited for sleeping on the water (away from land-based predators).
Woodpeckers tend to sleep in tree cavities while quail may sleep
in low-lying vegetation. Others, like shorebirds, which can’t sit in
trees or on the water, typically sleep out on open
beaches in large flocks for protection.
In addition to being able to sleep high up in trees without falling out,
some birds have developed the ability to sleep with one eye open,
which is known as unihemispheric slow-wave sleep (USWS).
Basically, they allow one side of their brain to fall into deep sleep
while the other side remains alert and on the lookout for predators.
Even more intriguing, birds can choose when to use USWS
and when to sleep fully – and some may even be
half-asleep during flight. As Slate explained:
“Birds can turn USWS on and off depending on how safe their roost is:
For example, when a large flock of ducks is roosting on an open lake,
the birds in the safety of the center of the flock may shut down completely,
while the more vulnerable birds at the edge of the flock may enter
USWS to stay alert. What’s more, scientists suspect that some
birds use USWS to sleep while in flight.”
Thanks to Dr. Karen Becker of Mercola Healthy Pets for
this article on the sleep habits of birds.
Julep and Derby
We're super busy packing boxes and moving them
into the storage unit. Time is running out and with
'Phil' seeing his shadow ... we are hoping we don't have a
blizzard on moving day.