XC EEPORT OF THE SECRETARY OF AGRICULTURE. 



between these races and some promising strains secured, one result 

 being that the irritability of some excellent honey gatherers can be 

 modified b}'^ using males of gentler races in the crosses. 



DIVISION OF BIOLOGICAL SURVEY. 



The Biological Survey is charged by Congress with three distinct 

 lines of investigation, each of which is organized as an independent 

 section of coordinate value with the ordinary Departmental division. 

 The first, or Biological Survey proper, studies the geographical dis- 

 tribution of mammals, birds, and plants with reference to the climatic 

 factors governing distribution, and from this study prepares maps 

 showing the boundaries of the natural life zones and crop belts of the 

 country; the second, or Section of Economic Ornithology, studies the 

 food and food habits of birds with relation to agriculture and horti- 

 culture; the third deals with matters of game preservation and intro- 

 duction. 



Biological Survey. 



California and Texas, owing to their great size, the diversity and 

 commercial value of their agricultural products, and their promise of 

 far greater development in future, have unusual claims on the Bio- 

 logical Survey. In California the work is peculiarly difficult by rea- 

 son of the extraordinary diversity of the topography and climatic 

 conditions. Not only are there torrid valleys below the level of the 

 sea, and alpine summits towering to elevations a])o^'e the limit of plant 

 growth; there are also areas of excessive humidity, of frequent fogs 

 and heavy rainfall, and areas of excessive aridity, hotter and drier 

 than the Sahara, where perpetual sunshine is the rule and 3'ears some- 

 times pass without rain. 



Owing to the trend of the principal mountains and the influence of 

 the coast fogs, the zones run in the main north and south instead of 

 east and west. Some of the large interior valleys, notablj'^ the Salinas, 

 act as flues through which a great volume of fog flows dailv at certain 

 seasons, lowering the temperature and increasing the humidity for a 

 distance of 75 miles or more. These great rivers of fog cut off the 

 sun, lower the temperature, and increase the humidity, and by over- 

 flowing through canj^ons and side vallej^s also reach and exert their 

 influence in numerous tributary vallej^s and basins, some of which lie 

 between the main fog river and the coast. In these cases the usual 

 conditions are reversed, for ordinarilv the vallej^s of the coast ranges 

 in retreating from the sea toward the interior receive less and less fog 

 and more and more heat and sunshine. Each valley and each moun- 

 tain slope therefore has its own climatic individuality and its own 

 capacity or adaptability for particular agricultural and horticultural 

 crops. Some are cool enough for apples, cherries, and the sugar beet; 



