Vol. 25, No. 3 
Page 2 
Several researchers have noted a relationship between breeding.rates and 
mast abundance. On our study site near Danville, however, correlations between 
breeding rates and production of white oak, black oak, red oak, and h'ckory 
seeds revealed no consistent relationships during the spring or fall. Apparently, 
mast abundance did not affect reproductive rates on that area. 
Weather conditions during the breeding period also have been implicated as 
important factors affecting reproductive rates. In our study, correlations 
between temperature and precipitation in the breeding periods (June and December 
January) and reproductive rates in the following per.ods (summer and spring, 
respectively) revealed no significant results, although June precipitation 
(r = -S. 5 I 1 ) and December temperature (r - -0.571) exhibited rather h.gh negative 
correlations. 
Finally, we evaluated the effect of population size on reproductive rates. 
Yearling and adult breeding rates were positively correlated and both were 
negatively related to adult and total population size the previous season. 
Yearling breeding was most highly correlated with population size (£ 0.80) 
suggesting that yearlings may be more sensitive to population density. 
Although the correlations performed do not demonstrate causative relation¬ 
ships, they suggest that reproductive rates may be negatively affected by 
population size. The large amount of variation in reproductive rates not 
accounted for by population size, however, suggests that a comp ex of facto , 
which may include weather conditions and food abundance, probably determines 
reproductive rates. 
Res ponses of Prai.rie Chickens to Habitat Manipulatio n “ »' 66 - R 
Between 1963 and 1981, 6,0^7 acres of grasslands were searched on foot for 
nests of 15 grassland-nesting species at Bogota. Redtop covered the most area 
(3,129 acres) and brome the least (282 acres). The 6 basic cover types used to 
provide nest habitat for prairie chickens were ranked according to nest 
densities. For 716 established chicken nests, the high-to-low ranking of cover 
was brome, timothy, weedy grassforbs (dominant species not read. 
redtop, prairie grasses (switchgrass, Indiangrass, and big bluestem), and wheat 
stubble-red clover. 
For 101 pheasant nests found during the annual nest searches from 19&9 
through 1981 at Bogota, the high-to-low ranking of cover was brome, weedy grass¬ 
forbs, prairie grass, timothy, redtop, and wheat stubble-red clover. Both 
prairie chickens and pheasants used all 6 cover types and both/Pf^hi rds and 
preferred brome. Brome also ranked high in nests of red-w.nged blackbirds and 
dickcissels, but relatively low in nests of bobwhite, meadowlarks, upland 
sandpipers, cottontails, and small mammals. 
Because of high use by nesting prairie chickens, brome merits increased 
consideration in prairie chicken management. Can brome be econom.cally managed 
