220 OUR USE OF THE LAND 



the Supreme Court, that Congress exercised a police power 

 usually left to the states. 



In order to protect these birds in the United States according 

 to the treaty terms as they fly from one home to the other, 

 the Migratory Bird Act was passed by Congress. This law 

 regulates the seasons during which the birds may be shot and 

 the numbers that may be shot. It also authorised the estab 

 lishment of bird refuges in certain parts of the country. These 

 refuges, which now cover about 4,500,000 acres, are nesting 

 and breeding grounds, such as marshes, lakes, and swamps, 

 spaced at intervals of about one duck-day's journey, along 

 each of the four main bird flight routes that span the United 

 States running north and south. Migratory birds, like the air 

 liners, fly regular routes, routes which they have followed for 

 thousands of years, routes which were apparently selected be 

 cause there were good natural breeding and feeding grounds 

 along them. 



More of an international problem is the regulation of fish. 

 With the exception of the fish caught within the three-mile- 

 zone around our coast, the fish belong to whoever catches 

 them. However, it is easy to see how this haphazard method can 

 cause endless complications. For that reason the United States 

 government has signed treaties with other nations whose fisher 

 men depend on the same supply that is used by Americans. 

 Canadian fishermen use the Grand Banks just as much as our 

 Gloucestermen. Japanese seal fishers depend on the seal supply 

 which originates in the Pribilof Islands. In order to maintain 

 a regulated use of these resources, and keep order between the 

 various groups of fishermen, the treaties lay down certain rules. 

 The Bureau of Fisheries and the Coast Guard administer these 

 rules for the United States. The outstanding success of this 

 type of regulation has been the preservation of the seal. Before 

 seal hunting in Alaskan waters was regulated, the seal hunters 

 were rapidly destroying the herds. Now with very strict con- 



