Vol..15, No. 12 
Page 3 
harvest levels and additional winter losses for both Forbes (_r = -0.967) and Dale 
(r = -O. 87 I). Total winter mortality among the quail populations, from the pre¬ 
hunt estimates to the prebreeding estimates, averaged 80 percent of the fall 
populations on Forbes and 77 percent on Dale. The negative correlations indicated 
that low winter losses offset high harvests and, conversely, that high winter 
losses occurred after low harvests. Bobwhite populations declined to 15 to 30 
percent of prehunt densities by the subsequent spring, regardless of the size 
of the harvest. 
Responses of Prairie Chickens to H ab i tat Manipulation R. L. Westemeier, 
D, R. Vance 
The original 16-square-mile (10,240 acres) Bogota Study Area was established 
in 1962 and in the summer of 1 963 was thoroughly cover-mapped. We completed 
another mapping of the area in 1972 in order to document land-use changes on* 
private land over the 10-year period. The dominant crop, soybeans, totaled 
about 4,200 acres or 41 percent of the study area in both years. Two major 
changes in land use occurred during this period--(l) corn acreage increased 
from 1,900 acres to 2,670 acres (18.5 to 26.2 percent of the total area) with a 
corresponding reduction in the acreages of small grains (primarily wheat), 
pasture, legume hay, undisturbed legumes, and grass hay; (2) prairie chicken 
sanctuaries increased from 77 acres to 635 acres. (The remaining 325 acres of 
sanctuaries at Bogota are outside the original study boundaries or have been 
acquired since the cover-mapping in 1972.) The total acreage of undisturbed 
grass increased slightly from 505 acres to 619 acres. However, undisturbed 
grass on private land decreased from 428 acres in l 963 to 188 acres in 1972. 
Undisturbed grass on prairie chicken sanctuaries increased from 77 acres to 
431 acres during the same period. In 1972, only about 78 acres of the 188 
acres of undisturbed grassland on private land could be considered good nest 
cover. 
The slight increase in the total quantity of undisturbed grass cannot 
account for the increase in the prairie chicken flock from about 156 birds in 
the spring of 1 963 to about 400 birds in the spring of 1972. Through the 
acquisition and management of sanctuaries, the 428 acres of poor-quality and 
hazardous nest cover available on private land in I 963 was replaced with 431 
acres of safe high-quality nest cover on sanctuaries by 1972. In short, an 
acre of grass on sanctuary land will support two to three times (or more) 
prairie chickens than an acre of grass on private land. 
