Vol. 10, No. 4 
Page 2 
At times, however, it has been possible to collect pheasants from marginal range 
(northern Coles County) and submarginal range (Neoga Release Area in Cumberland 
County), thus affording the opportunity for making quantitative comparisons of 
physiologic characteristics of pheasants from struggling populations with those of 
birds from thriving populations. 
During October 1966 and January 1 967 ^ 23 hen pheasants were collected from 
thriving populations, 14 from marginal range, and 17 from submarginal range. These 
hens were classified as 4-month-old juveniles, 7-month-old juveniles, and adults 
(birds more than 12 months old). It was found that, of the physiologic characteris¬ 
tics measured, no dramatic, clear-cut differences existed between pheasants from 
thriving populations and pheasants from the marginal and submarginal ranges. There 
was, however, a tendency for muscles to be slightly smaller in birds from thriving 
populations, intermediate in birds from marginal range, and larger in birds from 
submarginal range. There was also a tendency for the pancreas to be of reduced 
size in pheasants from the marginal and submarginal ranges. Probably the most 
interesting finding was differences in mean weights of the thyroid glands, which 
were consistently 10 to 20 percent less in birds from submarginal range than in 
birds from thriving populations and from marginal range. This was true in both 
absolute weight end relative to body weight. As the thyroid glands regulate 
metabolic rate, and the size of these glands is inversely correlated with their 
rate of activity, this could be an important finding. It would appear that 
pheasants subsisting in submarginal range have, on the average, a higher metabolic 
rate than birds in the established range. If this finding is correct, it is 
possible that pheasants in submarginal range "burn themselves out" in a relatively 
short time, which would reduce their rate of survival. 
4. Responses of Bobwh i tes to Habitat Manipulat ion J. A. Ellis, K. P. Thomas 
Whistle count data collected on the Dale (1964-66) and Forbes (1965-66) areas 
indicated that annual fluctuations in the numbers of cock quail and of calls per 
stop were directly related to prehunt population densities. The average number 
of cocks and of calls, recorded per stop from mid-May to mid-July, multiplied by 
5*9 and 1.4, respectively, would have yielded, with 99 percent confidence, the 
prehunt densities on the two areas. During l$66, for example, the average number 
of cocks per stop on Dale (4.5) was 2.1 times the value for Forbes (2.1); the 
prehunt density on Dale, expressed as bird per 100 acres (30.0), was 2.1 times the 
value for Forbes (14.0). For whistle counts to be valid indicators of fall popu¬ 
lations on the two areas, we must assume that production and mortality during the 
summer months, per calling cock, were relatively constant on both areas during the 
3 years of study. 
5* Responses of Prairie Chickens to Habitat Manipulation R. L. Westemeier 
Counts of booming prairie chickens on the Bogota Study Area between January 
10 and April 16, 1967, revealed a slightly increased number of cocks since the 
spring of 1 966 . The highest count of cocks, among 19 early-morning surveys in 
1967> was 45, 10 percent higher than the peak count of 4l cocks in 1966 . Between 
1965 and 1966 the population level remained essentially unchanged. Between 1964 
