cycles. In view of its widespread inortance, many additional investigators
must perforce become involved. It is difficult to decide what evidence is
pertinent without some working hypothesis as to the nature and mechanism
of the cycle. The purpos'e of this paper is to oresent such an hypothesis.
It is our hope to draw helpful criticism and to stimulate effort.
Our accumulated evidence is too tentative and voluminous to be
here presented. It will, however, be published,- that gathered by Leopold
now in preparation
in a report/on his Game Survey of the North Central States, and that gathered
by King at a later date.
Why Explain the Cycle?
The "Cause" of the game cycle is as yet unknown. Possible methods
of control are still entirely obscure. Is it worth while to look for the
cause? Having faund it, is it possible that methods of control might be
developed?
The sportsman's first reaction to this question is one of pessimism.
"You can't doctor wild birds, even if you knew how." This pessixistic reaction
is well justified if it be true titat the "sickness" or other cause of periodic
scarcity is an inherent characteristic of the species affected. A later
caption will  show, however, that there is a-t least a probability that the
"sickness" arises from the condition of the environment, rather than being
inherent in the species. At least a part of the environmental conditions
can be "doctored." The kind and distribution of vegetation, for instance,
is being "doctored" every day by axe, fire, and plow.  The kind and abundance
of natural enemies is being "doctored" every day, indirectly through vegetation,
and directly by trap and gun.  It is at least thinkable that the intelligent
guidance of these man-made changes in environment might eventually mitigate
or even cure the "sickness."