tality pressure against it when the prey population
is low. Predators of this type tend to maintain stability in a community
in contrast to the violent oscillations often caused by a more
stenophagous predator. This study indicates that in south-central Kansas
crows help to stabilize the populations of grasshoppers, ground-dwelling
beetles both predaceous and non-predaceous, and probably those of other
types of insects whose soil dwelling larvae are subject to predation
during summer plowing.

Crows also serve as scavengers, feeding on carrion and at dumping
grounds, as indicated by the high frequency of eggshell and mammalian
bone in the diet. Bird bones were found in an insignificant amount in
this study, but extensive collections were not made during the main
nesting season.

Summary

An intensive study of the yearly diet of crows was carried on from
December, 1952, to February, 1954, in Harvey County and the northeastern
townships of Reno County, Kansas, in order to discover some of the
ecologic and economic relationships of the population of crows in
south-central Kansas. The study is based upon the analysis of 617
regurgitated pellets collected throughout the year. Data obtained from
this analysis have been correlated with field observations on crows and
habitat changes.

The area is in the zone of transition between tall-grass and short-grass
prairie, and the predominant agricultural crop is wheat. The study area
supports a breeding population of approximately one pair of crows per
square mile, but large flocks of wintering crows move into the western
part of the area near the Arkansas River Valley.

Plant material amounted to 69.0 per cent of the pellet residues. Wheat
is the food taken in greatest amount in the yearly average, but the
staple foods of the wintering crows are grain sorghum, sunflower seeds,
and corn. Crows use newly sown oat fields as a major source of food in
late winter and early spring, but damage to the crop seems to be slight.
Growers of grain sorghum and, locally, growers of corn and watermelons,
sustain serious damage from crows.

Being euryphagous, crows exert a stabilizing influence on many kinds of
prey and on the biotic community as a whole. This study indicates that
their effects are especially important in helping to stabilize the
populations of grasshoppers and of ground-dwelling beetles, and possibly
those of some other insects that have soil-dwelling larvae.

Carrion an