8 THE EXTENSION 
ther investigation of the situation the scientific machinery 
of state and nation is at the service of the citizens. 
Economic Relations of Birds 
With reference to the general economic status of birds 
it is customary to classify them in four main groups as out- 
lined by A. K. Fisher: 
(a) Those wholly beneficial or wholly harmless 
(b) Those chiefly beneficial 
(c) Those in which the beneficial and harmless quali- 
ties seem to balance each other. 
(d) Those positively harmful. 
To determine in which of these groups a given bird be- 
longs involves a vast amount of patient labor including field 
observation, experimental feeding and study of the actual 
stomach contents of many birds taken in different places 
and at all seasons of the year. The matter is one of too 
grave importance to depend upon hasty judgments or casual 
observation. 
The principal services which birds render are usually 
grouped into: 
(a) The destruction of harmful insects, both those 
which prey upon crops and trees and those which spread 
disease. 
(b) The destruction of injurious mammals especially 
rodents, such as rabbits, gophers, ground-squirrels and mice. 
(c) The destruction of weed seeds. 
(d) Serving as scavengers by removing offensive and 
dangerous decaying materials. 
Birds are nature’s most efficient check in preserving a 
proper balance in nature, that is, in preventing the undue 
increase of insects, rodents and weeds. Where natural con- 
ditions are left undisturbed by man this balance is main- 
tained with remarkable perfection. But, civilized man is 
everywhere a disturbing element in this perfect natural har- 
mony. His activities and occupations usually tend to cause 
a reduction in the number of birds at the same time that his 
agricultural operations make conditions more favorable by 
providing shelter and additional food for the increase of in- 
sect, mammal and weed pests. One frequently hears the 
remark that there is no need to worry about those thing up 
here in North Dakota, that conditions are such that we shall 
never be bothered by them, especially insects. They used 
to talk that same way in what are now the older settled 
states and this complacent or ignorant attitude led to neglect 
of proper control over nature’s forces until now in spite 
