Mat 2, 1919] 



SCIENCE 



411 



mals, such as wolves, coyotes and others, have 

 been killing more than $20,000,000 worth of 

 live stock yearly on the western ranges, while 

 swarming' millions of rodents, such as prairie- 

 dogs, groimd squirrels, jack rabbits, field mice 

 and others, were destroying farm crops, or- 

 chards and forage to the approximate value of 

 $300,000,000 yearly. Through investigations 

 of representatives of the Biological Survey, 

 effective metliods have been developed for the 

 destruction of these pests on a lai^e scale. 

 These pests occupy such an enormous area, 

 however, that the cost of handling the problem 

 is a large one. Improvements in this work 

 are still possible and investigations are being 

 continued to devise still more economical and 

 effective methods. 



Recently other investigations have been be- 

 gun to determine with scientific accuracy, 

 through fenced plots of land in the west, the 

 definite amount of injury done to forage pro- 

 duction by the principal different kinds of 

 rodents. There is much room for cooperation 

 here and the results will be of the utmost 

 practical value. 



The Forest Service finds it impossible in 

 many places to accomplish successful reforest- 

 ing by seeding until the native mice, and 

 sometimes chipmunks and other rodents in the 

 vicinity, are destroyed. This leads directly to 

 the fact, which has become recognized only 

 recently among a few investigators, that mice 

 and other small rodents, common nearly every- 

 where and which swarm in surprising abun- 

 dance over vast areas exercise a great and at 

 times perhaps controlling influence on the 

 character of the vegetation prevailing, in- 

 cluding forest production. Dr. MacDougal, 

 of the Carnegie Desert Laboratory, at Tucson, 

 Ariz., informs me that he finds the small 

 desert rodents have a decided effect on the 

 character of the desert vegetation through 

 their destruction of seeds and of the sprouting 

 plants. The exact facts in regard to this rela- 

 tionship between rodents and the native vege- 

 tation are not definitely known in the case 

 of a single one among the hundreds of species 

 of these small animals. 



The study of our bird and mammal life and 



its relation to its environment, its distribution 

 and other factors in the life history of the 

 si^ecies are in part the object of the biological 

 surveys of the states which the Biological 

 Survey is conducting as rapidly as its means 

 will permit. These investigations include both 

 the field study of the birds and mammals and 

 the technical investigations relating to their, 

 taxonomic characters in the laboratory. To 

 enter into investigations such as those men- 

 tioned above requires a technical knowledge 

 of the sjDecies of birds and mammals. 



The house rat causes losses approximating 

 $200,000,000 yearly in the United States. One 

 of the greatest needs in controlling these pests 

 is an effective poison which they will take 

 freeb'. The investigator who discovers this 

 will do a great ser\'ice not only to this country 

 but to the world. Little exact knowledge is 

 available as to the relation of rats to the 

 spread of diseases of man other than bubonic 

 plague. 



It is also desirable and important to learn 

 whether other native rodents than the Cali- 

 fornia ground squirrel are susceptible to the 

 plague and can transmit it. The ground 

 squirrel named is known to be a plague 

 carrier. In important practical questions, such 

 as that of determining the disease-carrying 

 rodents, a technical knowledge of the various 

 species and their distribution becomes of 

 prime importance. 



Many of the government bureaus, including 

 the Biological Survey in the Department of 

 Agriculture, are now cooperating with agri- 

 cultural colleges and certain activities in uni- 

 versities. Yet the great majority of people 

 out of Washington do not generally appreciate 

 the real extent and variety of investigational 

 activity in the capital, not even men engaged 

 in related lines of work. The spirit of co- 

 operation, however, is growing. An instance 

 of this is the awakening interest of state insti- 

 tutions in the investigation of the relation 

 of rodents to the production of forage plants, 

 crops and other vegetation. A representative 

 of the Agricultural College of Arizona is 

 actively cooperating with the Biological Sur- 

 vey in a project of that character begun last 



