April 4, 2008
Inca Doves-sleeping
Inca Doves-sleeping
Remember last year when we said birds have the same three basic instincts we do:  eat, sleep, etc., we explored five mysteries revolving around how they found food  Today we're solving five mysteries about their sleep habits.

You're taking your daily walk and find a long, straight line of bird droppings beneath a tree.  Every day it's in the same place, but you never see any birds on the overhead branch.  Where does this stuff come from?

Many species that are gregarious will huddle, lined-up together, night after night on the same branch, the communal roost providing two essentials you need for sleeping too--warmth and security.  And they sometimes have to do the same thing you do in the middle of the night.

You're working in your yard early on a winter morning and see the local mockingbird sitting in a bush.  It looks noticeably bigger and fatter than you remember.  Are there steroids for birds?

Winter nights in the desert are cold.  Birds are able to fluff out their feathers to retain body heat, and many species do this overnight while sleeping, sleeking down only after the sun has warmed the atmosphere.  Northern species like chickadees and juncos could not survive the harsh winters of their environment without this adaptation.

You're driving down my block and notice a bird hanging upside down, holding on by one foot, from the upper branches of a deciduous tree, still leafless now in early spring.  Is this a feeding strategy you've never encountered before?

No, bad stuff happens in the avian world just like it does in yours.  During last winter's hard freeze, this starling froze to death on its overnight roost.  Somehow the tendons in one foot remained locked up in death, and now it hangs swaying in the breezes, a stark reminder of natures' immutable cycles.

You're watching the ducks on the local golf course pond.  One appears to be sleeping, head turned and resting on its back, eyes shut.  Every few moments, though, its eyes open for a few moments, then close again.  Perhaps it's sick or injured?

Although most diurnal birds spend the night sleeping, just like you they often break from their daily routine, become inactive, and take a nap, sometimes as brief as a few minutes.  Some birds actually sleep with their eyes open, and a species of Eurasian swift has been proven to sleep on the wing!

You're scanning the shorebirds at Gilbert Water Ranch when you realize one of the dowitchers has lost a leg.  It's standing in the water trying to sleep, balanced on one foot.  How is it able to survive like this?

Keep glassing and you'll discover several resting shorebirds have "lost a leg."  This family of birds is notorious for tucking one leg up under their body feathers while at rest, and many passerines do this too.  Legs are bare, and this behavior is thought to be a mechanism for maintaining body temperature.

Like you, birds need warm and secure sleep and, just like you, they have many adaptations which help them get it.