VERTEBRATES 145 



25. Name three bird magazines and give a characteristic 

 of each one. 



26. Fossil birds and the light they shed on the probable 

 ancestry of birds. 



Study of the Migration of Animals in General 



The migration of birds is only one case of a phenomenon 

 which is comparatively common. From your text and 

 reference books find other examples of migration. What 

 are the causes which make animals migrate ? What 

 methods do various animals use .■• What are some results 

 of these migrations ? Summarize your study in the follow- 

 ing thesis : — 



TAe distribution of animals. 



1. The necessity for this distribution. 



2. Methods of distribution — voluntary — involuntary. 



Note. — See in review the methods .used to spread corals, hydroids, 

 and other sedentary forms, starfish, clams, etc., as well as those used by 

 the various vertebrates. 



3. Time when migration occurs. Consider here the young 

 of most animals, and the movements of many birds, as well 

 as movements caused by some accidental occurrence. 



4. Distance that animals move from the place of their 

 birth. 



5. Factors which determine the routes of distribution. 



6. Factors which limit distribution. 



Migration maps. 



1. A map to show the migration route of the birds of 

 your region. 



2. A map to show the migration of the potato beetle (or 

 English sparrow or any other animal the extension of 

 whose range has been studied). 



