Prairie voles inhabit areas where the dominant plants in summer are
clover or grasses or both. The lawn on the campus at the University of
Kansas consists mostly of several kinds of grasses, but in some places
alfalfa (_Medicago sativa_) replaces clover (_Trifolium_ sp.), and in
other places sedges (_Scirpus_ spp.) are found in addition to the
grasses. The grass is short; it is mowed to a length of 4 to 6 inches.
Bluegrass (_Poa pratensis_) and crabgrass (_Digitaria ischaemum_) form
most of the sod. Bluejoint (_Andropogon furcatus_) is common in a
sparsely wooded part of the campus, an area which has many voles.
Foxtail (_Setaria lutescens_ and _S. viridis_) and prairie threeawn
(_Aristida oligantha_) are also common on the lawn, but these become dry
in late summer, and at that time supply neither food nor cover for the
voles. The voles make well-beaten depressions in the sod, and the grass
arches over them to form canopies.
In the winter, when the snow flattened the grass on the campus so that
there were no longer protective canopies of blades over the runways of
the voles, they migrated into areas of Japanese honeysuckle (_Lonicera
japonica_). At this season the honeysuckle was their main food. In areas
where this vine was not available, the voles abandoned their surface
runways and remained below the ground, coming to the surface only under
the protection of a blanket of snow. The voles returned to the grass and
clover habitat in March and April in 1946.
One pure stand of Ladino clover in Jefferson County, Kansas, was studied
in late November and early December of 1945. The clover was 2 to 4
inches high, and although it was the sole food of the voles, it
furnishes but little cover. They were common here; 300 traps yielded 111
voles in two nights.