A THEORY OF BIRD MIGRATION

Evening Post, Volume CXVII, Issue 65, 17 March 1934, Page 19

A THEORY OF BIRD MIGRATION

'The. theory of the unhampered life of ( feirds and the expression "as free as a bird" were challenged by Captain B. Acworth, when lecturing at a meeting ;of the Viefpria Institute at Westmin- . ster. -According to his theory, birds , apparently: have no free will, as to [ where.they fly; they are simply borne on the winds of chance, says'the" Manchester ; Guardian." ' . ..Captain. Asworth, in .. a paper on . ''Bird flight and its bearing on the ;,theory of evolution," pointed out that Darwin and" his disciples erroneously supposed that birds were free and could fly where they liked, and evolve and change ther nature to suit their new environments. "The laws of currents, and these alone, are responsible for the dispersal.of birds," declared Captain Acworth. "Subject to these laws, bird life ebbs and flows atiout the world in harmony with the great seasonal winds. In addition, to the seasonal winds, however, there are the permanent winds which impose impassable, barriers, and which, confine" the birds of the various species to localities agreeable to their specific- needs., "To the uninitiated observer, the power of flight must appear, almost inevitably, to confer freedom-"upon those equipped1;, to employ it, but; /creatures and airmen dependent upon flight for their movement are in reality in a state of bondage which no earth-bound'crea-ture experiences. Birds are absolutely parasitical to the air in which they fly, "which implies that under circumstances which regularly arise with the changing seasons, they will be compelled to leave their homes without any intention on their part.

''Herein lies the 'secret of 'migration.' It should, however, be pointed out at once that the Compulsion under which the bird lies to leave home eon stitutes a damaging*: criticism of the evolutionary theory that birds leave their homes as a result, of a biological urge handed down from prehistoric times." ! ■ Considering the migration, or, as he called it, the "drift" of the swallow, Captain Acworth said that when the equinox arrived the bird would drift great distances away from. its. home and in the direction towards which the prevailing wind was blowing. Day by day the process of drift would continue, the bird striving for home when not engaged in its primary business of feeding. It thus "migrated" backwards. Its drift was resisted, and in southern climes it was a homeless vagrant. The bird was cut off from its northern home by the winds of winter which, if turning southerly for a few days in a mild winter, would bring swallows unexpectedly,- to England while unusual mildness lasted.- In the spring, added Captain Acworth, the birds' autumnal drift' backwards was reversed into a northerly, drift home ,by the southerly and south-easterly winds of spring. The sequences of events, said Captain Acworth, was determined not by any gleam of memory or reflecting capacity in the bird, but by the changeless laws of physics and dynamics. If, therefore, birds were mindless, there' could have been no "evolution" of mind in birds. Neither could there be any common denominator between the brain of bird and man, as evolutionists claimed.