MONTHLY WILDLIFE RESEARCH LETTER 
Department of Conservation and Natural History Survey, Cooperating 
Glen C. Sanderson and Helen C. Schultz, Editors 
Urbana, Illinois September, I 966 Vol . 9, No. 9 
1. Pheasant Popu1 ations and Land Use S. L. Etter 
The standardized counts of pheasant broods, made on the Sibley Study Area 
during July and August 1966, revealed 7 percent more broods than were recorded in 
1 965 ^ but 23 percent fewer than were recorded in 1964. One hundred twenty-two 
broods were observed along 640 miles of roadside transect (two 40-mile routes were 
driven weekly), compared with 114 broods in 1 965 and 159 broods in 1964. The 
average size of broods judged to be completely counted was 5-3 chicks, compared 
with 5-1 chicks in 1 965 ^ an increase of 4 percent. 
The number of adult pheasant hens observed during July and August along these 
same 640 miles increased from 234 hens in 1 965 to 241 hens in 1966 (3 percent). 
Forty-nine percent of the adult hens observed in 1 966 were broodless, compared with 
54 percent in 1965* 
The above indices reveal a slight increase in production in 1 966 compared with 
1965. 
The number of adult cock pheasants observed on the standardized counts increased 
from 113 in 1965 to 179 in 1 966 (58 percent). This high proportion of cocks in the 
population has been apparent during the entire year and can be attributed to a 
light harvest during the 1 965 hunting season. 
2. Mar, i pu i at i on of Pheasant Hab i tat G. B. Joselyn 
During the years 1963*66 only a slightly higher rate of success is evident 
for pheasant nests established on seeded roadside plots, as compared with those 
established on managed control plots (Table 1). Sixty-one of 229 nests located 
on seeded plots (26.6 percent) were successful, compared with 32 successful nests 
of 150 established on managed control plots (21.3 percent). The success on seeded 
plots has varied from a high of 38.6 percent in 1963 to a low of 20.6 percent the 
following year, with no marked change evident during the past 3 years. The lowest 
rate of nest abandonment on seeded plots (11.4 percent) occurred in 1963; since 
then, this cause of nest failure has been fairly constant at between 19 and 25 
percent. On seeded plots, the rate of predation by large mammals has also been 
relatively constant the last 3 years (approximately 40 percent) but was only 30 
percent in 1963; in contrast, predation by ground squirrels has fluctuated, being 
highest in 1964 and 1966 , when 16 and 14 percent, respectively, of the nests were 
preyed upon by this mammal. The highest rates of nest success on seeded plots 
occurred during the 2 years of the lowest occurrences of ground squirrel predation 
(1963 and 1965)• 
Percentage success of pheasant nests established on managed control plots has 
increased substantially the past 2 years, the rate in 1 966 being nearly 9 percent 
higher than that on seeded plots. The increasing success of nests on managed control 
