346 



THE NATIONAL GEOGRAPHIC MAGAZINE 



some of the more newly opened Cana- 

 dian provinces, profiting by past experi- 

 ence, have established protective quaran- 

 tine regulations, which should for a long 

 period give these regions a tremendous 

 advantage over older fruit centers in 

 lessening the cost of production. 



It is useless now to dwell on what 

 could have been saved to the agriculture 

 and natural-forest resources of this con- 

 tinent if our forefathers had been wise 

 enough to have early established and 



intelligently enforced inspection and 

 quarantine regulations against the Old 

 World to exclude plant diseases and in- 

 sect enemies. That would have been con- 

 servation in its most practical form. The 

 past cannot be remedied, but the future 

 can be safeguarded, and that is the pres- 

 ent opportunity. The first step towards 

 securing the desired legislation is to 

 arouse a public realization of the need. 

 The moment this need becomes generally 

 felt, the legislation will be forthcoming. 



OUR GREATEST TRAVELERS 



Birds that Fly from Pole to Pole and Shun the 

 Darkness: Birds that Make 2,500 

 Miles in a Single Flight 



By Wells W. Cooke 

 Of the Biological Survey, U. S. Department of Agriculture 



THE migration of birds has long 

 been considered an unfathomable 

 mystery, but late investigations 

 have furnished abundant data on the 

 when and where of migration and solved 

 many of its puzzles. The Bureau of Bio- 

 logic Survey of the United States De- 

 partment of Agriculture has collected 

 much information on the migration of 

 North American birds, and this article is 

 an attempt to put in popular form some 

 of the data that have already appeared 

 in the more technical bulletins and re- 

 ports. No correct understanding of bird 

 migration is possible until it is con- 

 sidered as a voluntary evolution. All 

 migratory movements must have begun 

 with changes of location, which were 

 only very slight. 



From this short migration, benefit ac- 

 crued to individuals or to their posterity. 

 Migration became a fixed habit, and the 

 distance covered gradually — very gradu- 

 ally — increased as each succeeding exten- 

 sion proved advantageous. It is not to 



be supposed that every attempted exten- 

 sion was a success ; in fact, it is more 

 probable that only a small part of the 

 experimental pioneering routes were per- 

 manently adopted. 



Moreover, it must be borne in mind 

 that the time occupied in the establish- 

 ment of present migration habits and 

 routes was measured in geologic ages, 

 and there is no reason to suppose that 

 changes took place during these ages any 

 faster than they do now. 



It is about a hundred years since the 

 first reliable notes on migration in the 

 United States were recorded, and this 

 period has proven too short to show any 

 perceptible difference in its time, direc- 

 tion, or speed. It can be affirmed, then, 

 that the migration routes of today are 

 the results of innumerable experiments 

 as to the best way to travel from the 

 winter to the summer home and return. 



It can also be said that food supplies 

 en route have been the determining fac- 

 tor in the choice of one course in prefer- 



