Page:The Migration of Birds - Thomas A Coward - 1912.pdf/77

Rh by the perfected or best route which their experience has taught them. Martorelli wisely asserts that orientation is not infallible. but develops with age.

Mach-Bruer attempted to localise this sense of direction in the semicircular canals of the ear, which are so highly developed in birds, but Dr Allen contends that the theory has been refuted by experiments on pigeons. Möbius urged that birds were guided in their journey by the direction of the roll of the waves; Newton replies that though this may be a constant direction in certain parts of the Pacific, it is most inconsistantinconsistent [sic] in the stormy North Atlantic (37).

There is a very generally accepted idea that birds prefer to travel with the Wind striking them diagonally—the "beam-wind theory," a theory, which so for as I can see, has absolutely no sound foundation. When on the Kentish Knock Lightship, Mr Eagle Clarke noticed, on a bad day, east to west migrants hurrying past "as if to avoid as much as possible the effects of the high-beam wind."

Mr A. H. Clark worked out the long oversea and overland course followed by the American golden plover, and showed to his own satisfaction that the birds always travelled at right angles to the prevailing winds; therefore, he argued, they