A Red Knot

A red knot is a species of sandpiper that is found on coastal areas through out the world.  If you by chance  lost a piece of jewelery  – a ring, ear ring or watch you might want to call on a red knot to help you find it.

As they roam the beach they pop their beaks in and out of the wet sand in search of clams, snails and crustaceans to feed on and appear to be randomly doing it.

Researchers have had captive red  knots to see if they randomly poking in the sand or did the have a purpose to do this.  They did an experiment to see if they had a reason for their actions.  The researchers filled one bucket only with sand  and the other with stones and small shells to see if it made any difference in their behavior.  Both buckets were buried in the sand near to the red knots.   The stones and shells were buried deeper than their the length of their bills.

As it turned out,  the small sandpipers passed up the areas where the buried buckets with only sand however when the came to the areas where the buckets had stones and shells in they immediately began to stick their bills in the sand.

How did they detect the stones and shells?  As it turns out the bill of the sandpiper has a sensory structure built into its bill called Herbst’s corpuscles which sense changes in pressure.  When the birds are poking the sand with their bill it builds up pressure in the sea water surrounding the sand particles.  If there is a tasty clam near by the sensors in the red knot’s bill detects a disturbance in the pressure and the clams presence is given away.  This sensory capability makes the red knot an expert forager – leaving its prey no where to hide.

By Jack Kidd, with help from an article from The University of Texas Marine Science Institute in Port Aransas Texas.