THE GROUND SQUIRRELS OF CALIFORNIA. 



773 



Control Division of the State Commission of Horticulture." Results 

 obtained by this arrangement have demonstrated the advantages of 

 co-ordinating the work of the various agencies in fostering the upbuild- 

 ing of California's great horticultural and agricultural interests, by- 

 placing the control of rodent pests under the supervision of a well- 

 organized division, through which that particular phase of development 

 might be brought about with the greatest economy in funds and labor, 

 and with substantial results, to the state as a whole. 



The United States Public Health Service for years has waged active 

 campaigns on ground squirrels in counties about San Francisco Bay, as 



Fig. 60. Habitat group, Oregon Ground Squirrel (Citellus oregonus). 



a measure of protecting the population against bubonic plague, which 

 through diagnoses in 1908, was found to be carried, through the medium 

 of fleas, by ground squirrels. This federal service had been able, 

 through co-ordination of effort through a central executive office, to 

 accomplish a greater amount of control work than had any other agency 

 heretofore. 



The appointment of W. C. Jacobsen as superintendent of the Rodent 

 Control Division by action of the State Commissioner of Horticulture, 

 met with approval by the county horticultural commissioners, due to 

 the interest taken in assisting these county officers with his experience 

 acquired in conducting operations against rodents in some of the western 

 states. S. V. Christierson, county horticultural commissioner of San 

 Luis Obispo, through civil service examination, was named assistant 

 superintendent, and with the assistant secretary, C. A. Wilkins, has 

 charge of the main office of the Rodent Control Division in Sacramento. 



Since the organization of the division in January, 1918, educational 

 campaigns have been conducted by the Rodent Control Division in 



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