Wednesday, June 14, 2017

Nothing significant

Camouflage is a common trait across many animal species.  Local animals that use camouflage include such diverse species as White-tailed Deer (spotted fawns), Barred Owls, Wood Frogs, and Giant Water Bugs.  Many species use camouflage to hide from predators; others are predators that use camouflage to ambush their prey.  One of my favorite uses of camouflage involves the Killdeer (Charadrius vociferous).  Killdeer are a shorebird that are often found far from water.  In Mid-Michigan they can be found in lawns, farm fields, athletic fields, school yards, or any other place with short vegetation.

Adult Killdeer are tan/brown above with white throats, breasts, and bellies.  They have a pair of black bands running across the throat and chest and black marks face.  Males and females look alike.  Although they are not conspicuous, Killdeer are not truly camouflaged. 

So how do they use camouflage?

In case you missed it in the first photo, I have moved in closer for this picture
Camouflage is the primary method of defense for their nests and eggs.  Like most shorebirds, Killdeer nest on the ground.  They scrape out a shallow depression in bare soil, gravel, etc and then (sometimes) add rock and bits of bark to build up the nest.  Nesting on the ground, makes both the nesting females and the eggs susceptible to predators so if a predator (or a human being such as myself) approaches the nest, the Killdeer's first instinct is to get up and run away, leaving the eggs.

I am sitting on my nest!

I am now running away from my nest!
Have the eggs been abandoned to their fate?

Not quite!  Their camouflage protects them to a large degree.  Also, the Killdeer has one more ace up its sleeve - an act of theater.  To distract the potential predator away from the nest, the Killdeer goes into an elaborate, injury-feigning dance of limping and wing-dragging.  The predator sensing an easy meal, forgets the nest and focuses on the seemingly incapacitated Killdeer.  But to quote MacBeth
it is all
... a poor player
That struts and frets his hour upon the stage
And then is heard no more: it is a tale
Told by an idiot, full of sound and fury,
Signifying nothing.

Ow!  Ow!  Ow! Easy meal here!

The Killdeer is not injured at all.  When it has strutted and fretted enough to draw the predator away from its nest, the Killdeer takes flight and the predator is left wondering "what was that all about?"

Meanwhile, the eggs remain safely hidden in plain sight.  Another victory for the powers of camouflage.

Yay! Camouflage!

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