NATIONAL RESEARCH COUNCIL 111 
problems which will arise in connection with sanitation, it would be very- 
desirable to have at least one trained zoologist connected with the medical 
staff of each mobilization camp. 
4. Agricultural Work. — {a) Apphcation of principles of heredity to the 
improvement of breeds of domestic animals. 
(6) Study of physiology of reproduction with a view to increasing produc- 
tivity in animal breeding; for example, improved methods of incubation, 
brooding and rearing of fowls; better methods of increasing egg laying, espe- 
cially during winter months; the serious problems of abortion in cattle, small 
litters and destruction of young among swine, etc. 
(c) Determination of standards of feeding and care of domestic animals 
for best general or specific results and for greater economy. 
(J) Cooperation with the agricultural agencies of the states and nation in 
the elimination of animals which prey upon or are parasitic upon domestic 
animals; of animal pests destructive to crops, fruits, forests, — to stored vege- 
tables, grains and other food siiipplies,— to clothing, woodwork and other 
manufactured products. The annual losses due to such animal pests are 
probably not less than the enormous taxes levied for the prosecution of the 
war; here is a perennial tax which would relieve us of all national taxation if it 
could be saved and applied to that purpose ; here are problems which call for 
research work of the highest order and for an army of investigators. 
{e) The protection of insectivorous birds and the propagation of enemies 
of injurious insects. It is estimated that in Kansas alone the annual pre- 
ventable damage to food crops amounts to thirty million dollars. The largest 
natural elements in the prevention of this loss are ground-nesting birds. 
Migratory birds should be protected by the passage of the ^'Migratory Bird 
Treaty Act." 
In this connection the Chief of the Biological Survey has written: 
"The National Stock Growers Associations estimate that the annual losses 
in live stock from predatory animals in the Western United States amount to 
from $12,000,000 to $15,000,000. The directors of extension work in the 
Western States estimate that the losses in cereal and other crops through 
depredation of noxious rodents in the four states of Montana, North Dakota, 
Kansas and CaUfornia, amount to between $50,000,000 and $60,000,000. I 
have determined that, at a cons»3rvative estimate, the damage done by house 
rats each year amounts to $200,000,000. This involves the continuous labor 
of more than 200,000 men. This is entirely apart from the very serious losses 
and deaths through the disease carrying proclivities of these animals. The 
work of conserving and increasing our migratory birds through the Migratory 
Bird Treaty with Great Britain is another important activity of this Bureau. 
The Canadian Government is now proceeding to secure enactments necessary 
to make the Migratory Bird Treaty effective on the recommendation from 
Government officials that to do so will assist in protecting the crops through 
the better protection of insectivorous birds." 
