Vol. 10, No. 8 
Page 2 
*■$ eggs before beginning to incubate. As a comparison, the same techniques 
indicated that the "average" hen in 1 966 began laying April 30 (range April 18- 
May 9) and laid 34 eggs before incubation began. These findings suggest that 
both the onset of laying and the number of egos laid by hens in the state's 
better pheasant range were similar during the 2 years 1966 and 1967 . 
4. Responses of Bobwhites to Habitat Manipulation J. A. Ellis, K. P. Thomas 
The juvenile/adult age ratios of cock quail collected by the cock-hen 
trapping method in 1 967 were .84 and 1.11 for the Forbes and Oale areas, 
respectively. These ratios were lower than those determined for 1 965 or 1 966 
and supported the viewpoint of a previous report (Monthly Wildlife Research 
Letter, Vol. 9, No. 8 ) that mild weather from January through March resulted in 
a decrease in the juvenile/adult age ratio of cocks. 
The prehunt populations on Dale and Forbes increased from 1 965 to l 966 ; 
the corresponding juvenile/adult age ratios of cocks, determined from the cock- 
hen trapping method, decreased from 1965 to 1 966 - If this pattern continues, 
we may expect the prehunt populations of I 967 to exceed the levels of I 965 and 
1966 . 
5- R esponses of Prairie Chickens to Habitat Manipulation R. L. Westemeier 
As of August 20, 1967, 11 prairie chicken nests have been located on the 
* Bogota Study Area. Five (45 percent) of these nests hatched, five nests were 
destroyed by predators, and one nest was destroyed by plowing. This year's 
predation rate on prairie chicken nests is the highest thus far recorded for the 
years 1963~67 at Bogota. Most, and perhaps all, of this summer's nest predation 
was believed due to striped skunks. 
One apparent reason for the higher rate of predation on prairie chicken 
nests in 1967 may be the drastic decline since 1966 in the vole ( Microtus sp.) 
population, which serves as a food supply for skunks and other predators. The 
2,001 Microtus nests counted on the Yeatter and McGraw sanctuaries in 1966 
represented a density of 23 nests per acre. In 1 967 a density of only one nest 
per acre was found on these areas, representing a 96 percent decline since 1966 . 
The scarcity of raptors at Bogota during the 1 96 7 booming season and during the 
winter of 1966 - 67 , as compared with an abundance of raptors 1 year earlier, 
provides further evidence of the current unavailability of voles as a food supply 
for predators. 
6. Rabbit Management J. A. Bailey, J. C. Hanson 
Production of soft food pellets (as opposed to hard fecal pellets) by caged 
adu 1 t cottontails on a diet of commercial rabbit food was measured during March 
27-31 and June 20-23, 1967* All animals had been captive indoors in their 16- 
x 24- x 13-inch wire cages for at least 18 weeks before the tests began. Pro¬ 
duction of food pellets was measured for six rabbits during each period. How¬ 
ever, three animals were involved in both tests. Thus, nine animals were involved 
» in the 12 determinations of food-pellet production. 
