Information regarding new developments and improved practices in
control procedure has been made available to the field personnel and
to cooperators of the bureau from time to time since the inception
of the cooperative work in 1915, in mimeographed and printed form,
as well as by individual written instructions and personal contact.
It is now desirable to compile the more important of the statements
as to policy and specific directions in one publication. All control
methods are based on fundamental research and give due consideration
to safeguarding the useful and harmless forms of wild life and the
public interests in general. Field methods have been adapted to meet
varying local conditions as called for by research and the experience
of field forces. Investigations and experiments are being continued,
and as additional information becomes available, field practices will
be subject to such modifications and improvements as the conditions
warrant.