. Bio-ecology. Plant ecology; Animal ecology; Botany; Ecology; Zoology. MIGRATION OF BIRDS 207 far the direction of migration is dependent on external factors. Light and topographical conditions have apparently no influence at all on the direction taken by the migrant swarms. As against this, it ap- pears possible that the wind plays a certain role; in the majority of cases investigated the hoppers were driven by the ;. Fio. 48.—Migration routes of North American birds. Though this map was pre- pared chiefly to show the flyways used by waterfowl, most of these routes also are utilize
. Bio-ecology. Plant ecology; Animal ecology; Botany; Ecology; Zoology. MIGRATION OF BIRDS 207 far the direction of migration is dependent on external factors. Light and topographical conditions have apparently no influence at all on the direction taken by the migrant swarms. As against this, it ap- pears possible that the wind plays a certain role; in the majority of cases investigated the hoppers were driven by the ;. Fio. 48.—Migration routes of North American birds. Though this map was pre- pared chiefly to show the flyways used by waterfowl, most of these routes also are utilized by innumerable land birds. For example, the important Mackenzie Valley-Great Lakes-Mississippi Valley route is shown (with its tributaries) from the Arctic coast to the delta of the Mississippi River. (After Lincoln, 1935.) MIGRATION OF BIRDS The migration of birds is presented rather fully because it is a universal phenomenon of great interest and significance. IMuch atten- tion has been given to it, and the diversity of opinion engendered has led to endless and often fruitless discussion (cf. Walter, 1908).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Clements, Frederic E. (Frederic Edward), 1874-1945; Shelford, Victor E. (Victor Ernest), b. 1877. New York, J. Wiley & Sons, inc. ; London, Chapman & Hall, limited
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Keywords: ., bookcentury1900, booksubje, booksubjectbotany, booksubjectzoology
