No. 114: Nov-Dec 1997
Earthworms have a potentially fatal habit: When they detect vibrations propagating through the ground, they quickly squirm their way to the surface. Perhaps they think a mole is tunneling after them, or maybe rain is beating down above. Whatever goes through their "minds," they emerge on the surface in response to vibrations and may be snapped up by several species that know their weakness.
Human fishermen know the worms' weakness and "grunt" for them in several ways; say, by drawing a notched stick across the trunk of a small tree to generate vibrations. Wood turtles are said to "stomp" for worms. (SF#65) Kiwis and Kagus also stomp for their dinner. (Kagus are rather strange birds found in New Caledonia.) We have just learned that Woodcocks will beat their wings against the ground to coax earthworms within range.
(Hennigan, Tom; "A Wonderfully Bizarre Bird," Creation/Ex Nihilo, 19:54, September-November 1997.)
Comment. Woodcocks seem to lure worms to the surface in still another way: They "bob" or "rock" their body in a most peculiar manner. It is thought that the resulting pressure waves are transmitted to the ground through their feet and that these bring their favorite prey to where they can be grasped.
(Marshall, William H.; "Does the Woodcock Bob or Rock -- and Why?" The Auk, 99:791, 1982.)
|The American Woodcock -- a very strange bird, said to fly off with its chicks clasped between its thighs!|