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 and material from dumping grounds furnish another fairly constant component of the crow's diet.

Table 1. Average, Maximum, and Minimum Percentages of Food Residues in Pellets Collected in Eastern Harvey County, in 1953.

April 6-19 June 15-28June 29-July 12July 13-26July 27-Aug. 9Aug. 10-23Sept. 7-20Sept.21-Oct. 4 Oct. 5-18Oct. 19-Nov. 1 Nov. 2-15 Nov. 16-29Nov. 30-Dec. 13
Number of pellets 9 7 6 19 18 5 57 29 27 24 25 7 8
No. of collections 1 4 4 4 4 2 5 4 4 3 5 1 2
wheat 18.2 34.4 1.7 35.7 28.5 29.0 23.4 21.5 10.8 35.4 33.0 43.7 49.1
(90-5)(99-50) (10)(80-10) (80-5)(55-20)(100-5)(100-5)(60-15)(85-10) (80-35)(98-30)(98-20)
sorghum 2.0 10.7 14.0 7.6 24.4 24.7 28.6 6.9
(35)(90-10) (75-5) (60-3) (85-5)(100-10) (80-5)(40-15)
oats 72.6 1.6
(99-50) (30)
sunflower seed 6.4
(40-5)
corn 4.5 4.0 1.4 15.0
(50-10) (80-10) (10)(70-50)
grass seed .5 44.6 28.6 4.8
(5) (90-60) (85-5) (70-5)
grape .1
(2)
cherry 20.1 1.7
(70-20) (10)
spurge .8 .1 .2
(5) (2) (5)
misc. plant 1.6 5.2 4.4 1.6 2.1 5.5 2.9 14.3
(30-10) (95) (90-40) (45) (50) (75-10) (20)(70-45)
TOTAL PLANT 90.8 54.5 4.2 39.5 80.3 57.6 39.0 39.9 20.0 66.6 67.2 83.0 85.3
scarabaeid beetle 28.7 5.0
(75-25) (30)
other beetle 2.7 .1 34.2 48.7 10.0 21.0 19.0 10.6 15.5 13.9 14.4 5.3 2.5
(10-5) (3)(100-20)(90-10) (90-10)(45-10)(80-5) (95-5)(98-1) (70-5) (65-5) (15-2) (20)
grasshopper .1 6.6 10.9 4.2 15.0 23.4 36.3 59.6 11.8 14.3 10.3 4.4
(2)( 40)(40-5) (40-5)(30-5)(100-5) (95-5)(90-34) (65-5) (99-5) (65-2)(10-5)
ant 5.9
(90-75)
misc. insect 1.9 2.8
.5(50-5) (60)
crayfish .5 1.5 35.0 .6 1.0 1.2 .2 .4 1.4
(5) (10)(100-10) (10) (5)(25-10) (5-2) (5-2) (20-10)
snail .6 .6 1.3 trace 1.1 .2
(10)(10-2) (20-5) (1) (10-5) (5)
fish .1 .1 4.8 7.3 2.5 3.4 .6
(7) (5)(20-5) (20.5)(20.1) (20-5) (10-5)
bird 15
(90)
eggshell .3 .6 3.0 2.0 1.1 .4 .2 .8 .7
(5) (10)(10-5) (30-5) (10-5) (1) (5) (20) (5)
mammal 6 15.1 3.7 1.4 2.2 .5 1.6 1.6 2.5 .7 7.8
(45-10)(100-5) (50-5) (5-2) (60-2) (5) (20-2) (10-5) (20-1) (5)(25-2)
TOTAL ANIMAL 9.2 45.5 95.8 60.5 19.7 42.4 61.0 60.1 80.0 33.4 32.8 17.0 14.7