whe re 
Vo 1. 9, No. 8 
Page 4 
ft 
Nsb = number of juveniles in the fall sample, 
Nsi = their survival rate, 
Nsc = number of juveniles in the spring sample, 
I'iob = number of adults in the fall sample. 
No i = their survival rate, 
Noc = number of adults in the spring sample. 
For the winter period of 1965-66 juvenile cocks had survival rates of 1.21 
and 1.26 times those of adult cocks on the Dale and Forbes areas, respectively. 
The survival rates of juvenile cocks for the winter period of 1964-65 were 1.58 
and 1.70 times those of adult cocks on the Dale and Forbes areas, respectively. 
In a previous report (Monthly Wildlife Research Letter, Vol. S, No. 5, 
May 1966), comparisons were made of the numbers of quail found during the post¬ 
hunt (January) censuses and the prebreeding (March) censuses for the years 1964-66. 
The greatest percent losses from January to March occurred in 1965, 64 and 50 per¬ 
cent on Dale and Forbes, respectively. In 1966 the loss from January to March 
was approximately 20 percent for both Dale and Forbes. The magnitude of these 
losses (January - March) was influenced by weather conditions. We may assume, 
therefore, that the survival rate of adult cocks to that of juvenile cocks is 
greater when the population is not subjected to unusually adverse weather conditions 
from January to March. 
5* Resporses of Prairie Chickens to Habitat Manipulation R. L. Westemeier 
The fourth annual search for prairie chicken nests on the Yeatter and McGraw 
sanctuaries at Bogota was conducted between June 20 and July 21, 1 966 . Private 
farmlands which were plowed or mowed were searched prior to this period, and other 
acreages were searched later. In all cases, possible harassment to nesting hens 
by the searching activities was held to a minimum. The total of 276 acres searched 
by August 20, 1966, includes 222 acres searched on foot and 54 acres searched with 
a truck-mounted flushing bar. The flushing bar technique was used in fields that 
were to be plowed within a few hours or a few days. 
Seven prairie chicken nests were found as of August 20 in the following 
locations: Yeatter Sanctuary, four; McGraw Sanctuary, one; private farmland, 
two. At least 9 other nests (possibly as many as 16) were reported by farmers, 
all but 1 of which were destroyed by spring plowing. No nests were found on the 
60-acre Donnelley Sanctuary. The other five sanctuaries (newly acquired) were 
not searched, since they are either not seeded or have recently been seeded and 
provide either no nesting cover or cover of poor quality. 
The five nests found on the Yeatter and McGraw sanctuaries were all success¬ 
fully hatched nests which produced a minimum of 50 young prairie chickens (Table 
4). However, the effectiveness of these two sanctuaries in their present state 
of management is discouraging from the following standpoints: (1) In 1964, 15 
nests were found on the Yeatter Sanctuary, producing 83 chicks, and 2 nests were 
found on the McGraw Sanctuary, producing 5 chicks. (2) In the spring of 1966, 
at least 15 hens (possibly as many as 17 individual hens) visited the booming 
ground that became well established on the plowed portion of the Yeatter Sanctuary. 
Thus, the 1964 nesting study revealed that a high density of nests was possible 
on the Yeatter Sanctuary, and the booming ground observations in 1 966 showed that 
