174 ANNUM, TJF.POKTS OF DEPARTMENT OF AGRICULTURE. 



importations of live birds and wild animals. Under a system 

 modeled after that of western Australia, and in cooperation with the 

 Customs Service of the Treasury Department, a system of permits 

 was carried into effect which has made it possible to trace each con- 

 signment imported from abroad, and to exclude any injurious 

 species. 



For the fiscal year ending June 30, 1912, the total number of 

 mammals imported from abroad was 5,457, and the total number of 

 birds 457,077. In other words, we are now importing foreign birds 

 (chiefly cage birds) at an average rate of more than 1,000 a day, 

 and a systematic record is kept of all such importations at each of 

 the entry ports of the United States and in Hawaii. 



Xo other country has undertaken so comprehensive a system to 

 prevent the introduction of species which may become injurious to 

 agriculture. Congress, recognizing the increased field of operations of 

 the office, raised the division to the rank of a bureau on July 1, 1905. 



DISTRIBUTION AND HABITS OF NATIVE MAMMALS AND BIRDS. 



The basis of most of the work is scientific investigation, and in 

 this field the most notable accomplishments have been the systematic 

 collection and publication of data regarding the distribution and 

 habits of native mammals and birds, and the preparation of maps 

 showing the natural life zones of the country. Each of these zones 

 is especially adapted to the growth of special crops and marks the 

 limits within which certain varieties of fruits and cereals produce 

 the greatest yield or beyond which they are not likely to be com- 

 mercially successful. 



Maps showing the ranges of individual species have also been 

 published, and have proved useful in cooperative work with the 

 Public Health Service in outlining the range of mammals which 

 carry the tick responsible for the deadly spotted fever in the Bitter 

 Koot Valley, Mont., and the area occupied by the ground squirrels 

 in California which transmit bubonic plague. 



Maps have also been prepared showing the distribution of other 

 species of ground squirrels, of pocket gophers, prairie dogs, wolves, 

 and coyotes, all of which are extremely destructive to stock and 

 agricultural interests in the West. The survey has mapped the 

 ranges, determined the abundance, and studied the habits of many of 

 the North American mammals and birds, and the knowledge thus 

 gained makes it possible to cope with most of the economic problems 

 in which native species are involved. Detailed studies have been 

 made of certain regions of special interest, notably of Mount Shasta, 

 Cal., and of the States of Colorado and Arkansas. A report has been 

 published on the birds of Arkansas, forming the first complete list 



