The habitat at Sixteen Mile Lake, chiefly deep coniferous
forest, is quite different from either the Baker Creek Valley or
the Bouchie Lake regions Trapping along old trails, by a small
creek, and in forest clearings, revealed that the meadow vole and
the red-backed vole had reached almost plague proportions while
mice and shrews were more abundant than elsewhere. During the
twenty-four hours following 8:30 p.m., August 21, a total of 54
animals, chiefly voles, was captured in 36 traps. In this time
one trap set across a runway, which passed under a wood pile,
caught nine mammals and during the entire trapping period of
eight days a total of 19 was captured in this trap. The number
of all species taken in 302 trap-nights totalled 227 of which 176
were voles. Nineteen of the total number were partly eaten in the
traps, by voles or shrews, before being recovered. So far as
could be learned no fur-bearing animals nor raptores were attracted
to this abundant supply of food.

Nowhere else were small mammals found in such numbers. Speci-
men returns on a trap-night basis in other localities are as follows:

Sumit Lake, 82, Nukko Lake, so Rocher Deboule, =.

It is well-known that mice and voles constitute one of the
main sources of food for various kinds of fur-bearing animals and
it is believed that voles represent the element of chief importance
in this food potential. oles are sedentary animals whose life-
span normally is spent within a narrowly circumscribed area and
thus they represent a more accessible food than do the free-moving
mice

It seems necessary to emphasize the fact that the cycles of
different species in the various groups do not usually coincide
in time. In any given region mice of one species or another may
be scarce at a time when one, or perhaps two, species of voles are
abundant, or the opposite condition may prevail. The periodicity
cycle if uniform in time over a large territory might be disastrous
to the fur-bearing animals which feed upon them; operating locally
it becomes a survival factor of importance. This staggered cycle
may also explain why mass movements of small carnivora from one
place to another sometimes occur.

It is not known to what extent carnivorous fur-bearing animals
feed upon shrews; they are repellent to domestic cats and a distaste
for them may be general amongst the small carnivora. However, it is
of interest to point out the fact that the cyclic pattern of shrews
operates on the same local basis as does that of voles and mice.

HGR