Vol. 12, No. 2 
Page 3 
5- Responses of Prairie Chickens to Habitat Hanipul ation R. L. Westemeier 
It was reported in the preceding research letter (MWRL 12(1):2) that the toler¬ 
ance limit in nest spacing of prairie chickens appears to be about 120 yards, judged 
on the basis of hatching success. Seventy-five percent of 20 nests destroyed by pre¬ 
dation at Bogota had a nearest-neighbor spacing of less than 120 yards. 
The spacing between nests in relation to the clutch size of nests provides addi¬ 
tional evidence that nesting prairie chickens require a certain amount of space for 
maximum efficiency in production. Clutch sizes of 15 nests increased as the nearest- 
neighbor spacing between nests approached 120 yards (r = 0.595, £*£0.05); 23 nests 
separated by greater distances showed no apparent change in clutch size. Interpreta¬ 
tion of these data is complicated by insufficient information on (1) the time when 
the nests were initiated and (2) by the possibility of renesting. However, the prairie 
chicken is essentially a "one-shot" nester with limited renesting ability, so the 
effect of these variables may be minimal. 
These behavioral patterns emphasize that vegetation on sanctuaries should be 
maintained in an attractive condition for nesting so that optimum spacing of nests 
can be manifested. 
6. Rabbit Management K- P. Thomas 
A total of 780 rabbits were harvested on the Forbes Area in l 968 and 726 in 1967- 
Of those killed in 1 968 , 617 were harvested by the 293 hunters who sought rabbits 
only; in I 967 a greater number of rabbit hunters (321) killed 593 rabbits. Rabbit 
hunters in 1967 and 1968 spent approximately the same amount of time in the field, 
3-9 and 4.1 hours, respectively, and harvested 0.5 rabbit per hour in both 1967 and 
1968. These data indicate that the rabbit populations of 1 967 and 1 968 were approxi¬ 
mately the same on the Forbes Area. 
In 1968, 187 rabbits were tagged on Zone I (sharecrop-burn) prior to the hunting 
season. Forty-seven of the tags were returned by hunters. The population in Zone I 
was estimated, using the Lincoln Index, to be 1,066+282, or 4 rabbits per acre. The 
harvest of rabbits by all hunters on Zone I was 268, or 25 percent of the rabbits 
available. Because the percentage harvest of cottontails was only 25 percent, the 
kill may not adequately represent the abundance of rabbits available to the hunters 
during 1968 . 
G- B. Rose 
During the fall trapping period on the 4-H Area at Allerton Park in 1968, lengths 
and weights of captured cottontail rabbits were recorded on the first date of capture 
in each month, and weight-length relation 
indices, using the formula: C.l. = ^ ^ 
L 5 
is the length in decimeters (Bailey, J. A. 1967- MWRL 10(7):3)* The mean condition 
index for October (37 animals) was 5*67, for November (100 animals) was 5*58, and for 
December (44 animals) was 5*65* The differences between means for the 3 months were 
not statistically significant at the 95 percent level of significance, although Bailey 
had found highly significant (£^.0.005) differences among the months November through 
March. 
ships were used to calculate condition 
E , where W is the weight in grams and L 
