THE EX'’TENSION 9 
of spending much time, labor and millions of dollars an- 
nually in combatting these pests by artificial means, the 
people are constantly suffering defeat and enormous losses. 
No thoughtful, careful observer can fail to see that these 
conditions are developing in North Dakota. Only ordinary 
intelligence and foresight are required to see that eternal 
vigilence and the employment of all the natural means to 
keep these pests from multiplying is our only hope of es- 
ecaping continually increasing losses. Already large sums 
are being spent in spraying operations against insects and 
single counties are spending amounts running to thousands 
of dollars annually distributing poison to decrease the num- 
ber of gophers. The annual loss to the grain producers 
through the depletion of the soil, lessened yield in spite of 
increased labor and lowered grade of grain because of the 
presence therein of weed seeds is perhaps even better ap- 
preciated by most farmers. 
The following data taken largely from the reports of 
the Bureau of Biological Survey of the U. 8. Department of 
Agriculture, can be confidently accepted as applying well 
to North Dakota conditions. Large numbers of bird 
stomachs have been examined and field studies made in 
connection with the Economic Biological Survey of North 
Dakota which give abundant warrant for the above state- 
ment. The detailed results for North Dakota will be com- 
piled and reported in due time. (See account of Biological 
Survey beyond.) 
Birds and Insects. In order to appreciate the work of 
birds in holding in check the increase of insects one should 
remember that this work is continued by different species 
all the year through both by day and night, that birds eat 
a much larger amount of food in proportion to their size 
than most animals, that not only the adult breeding in- 
sects are destroyed, but their eggs and young are eaten in 
enormous quantities and thus their development and _ re- 
production are prevented. One should recall also that if 
unchecked the offspring of a single adult female insect 
living from spring to fall will run from hundreds up to 
hundreds of millions depending upon’the species. ‘Think 
what it means to have only a single one of these insects 
killed in spring as you consider the following facts. The 
damage now done by insects in the United States amounts 
to several hundred millions annually the entire loss for 
1909 being estimated by Dr. L. A. Howard, Chief of the 
U. S. Bureau of Entomology as $1,200,000,000.. This means 
several dollars for every person in the entire population of 
