Vol. 12, No. 3 
Page 3 
less, on the average, in grit from Neoga (36.2) than in grit from Sibley (78.2); the 
difference was highly significant (_P<0.01). These findings add substantially to 
accumulating evidence that calcium might be influencing the distribution and 
abundance of pheasants in Illinois. 
4. Responses of Bobwhites to Habitat Manipulation J. Ellis, P. Matthews 
Levels of prehunt populations of quail on the Forbes Area have been correlated 
with the median dates of hatch (£<C0.05). The later the median dates of hatch the 
higher the resulting fall populations. These data were obtained from 610 wings 
collected during the 1964-68 hunting seasons and aged by molt criteria. Thus, quail 
hatched late in the nesting season contribute significantly to fall populations. 
Increased survival of late-hatched quail is probably the explanation for this 
phenomenon. Data from the Dale Area indicated a similai but not statistically 
significant--correlat ion. 
5* Responses of Prairie Chickens to Habitat Manipu1 at ion R. L. Westemeier 
As reported earlier (MWRL 11(12) :3) , the distance between a booming ground and 
the preferred zone for nesting appears to be about 240 yards. A correlation 
(r = -0.874, P<0.01) in support of this finding is that declining populations of 
prairie chickens at Bogota (1363-64) were associated with mean booming ground-to- 
nest distances greater than 500 yards; relatively stable populations (1965~66-67) 
were associated with mean distances of approximately 400 yards; and a population 
increase (1968) was associated with a mean distance of 293 yards. Although 
inadequate nesting habitat and spring plowing were important decimating factors 
acting on the population in preceding years, the above correlation indicates that 
increased advantages in reproduction were possible as annual mean distances from 
booming grounds to nests approached the preferred zone for nesting. 
8- Rabbit Management p - Thomas 
Trapping effort on the sharecrop-burn zone of the Forbes Area during the period 
February 5-28, 1969, produced 132 captures of cottontails; 54 original captures, 
34 captures of rabbits tagged during the fall of 1968, 3 mortalities, and 41 
recaptures. 
Sex differentials among the captures were; original captures, 29 males, 25 
females; recaptures (from the 54 original captures), 7 males, 15 females, captures 
of rabbits tagged during the prehunt period, 7 males, 27 females. Females comprised 
55 percent of the rabbits tagged during the prehunt period, but this difference was 
insufficient to account for the 7:27 ratio among recaptures. These data indicate 
that males were less prone than females to be recaptured even several months after 
their original capture, that males had a higher mortality rate than females, or 
that males had a higher rate of emigration than females. 
► 
