MIGRATORY INSTINCT

Hokitika Guardian, 18 October 1930, Page 6

MIGRATORY INSTINCT

Reversing the instinct of migratory birds so that they fly blindly northward in the middle of winter to face starvation :in country covered with snow and ice instead of southward where food would be found is the latest accomplishment of Professor William Roman, of the University of Alberta, Canada, who has been studying for years tlie causes of these mysterious bird migrations, and whose latest results have been announced through the National Academy of Sciences in Washington, D.C. Some time ago Professor Rowan formulated the theory that birds migrate southward in spring and northward in autumn because 'A changes are brought by the changing amount of daylight during the twenty-four-hour day at different seasons—less daylight in the winter and more in the summer. To test this idea a number of wild crows were trapped m the late summer and confined in cages provided with artificial lights which could be turned on or off as needed, thus producing artificial daylight for as many hours of the twenty-four as the experimenter desired. As winter came on and the hours ol natural daylight grew shorter the captive crows were given artificial light equivalent to longer and longer days instead of shorter and shorter ones. Two important things occurred. The birds’ glands increased in size as they normally do in spring. Also when these birds were released in mid-winter all or nearly all of them apparently migrated northward instead of southward, as was indicated by captures of marked birds far to the, north of where they were released. Further experiments are planned fo next year.