Vol. 22, No. 9 
Page 3 
Table 1. Minimum abundance of squirrel-food producers needed to support a 
squirrel density of 1/acre in winter. The number needed for each species is 
based on average seed yields and the amount of seed of each species eaten by 
squirrels in winter (October-March). 
Wh i te 
oak 
Black 
oak 
Black 
walnut 
Mockernut 
hickory 
Shagbark 
hickory 
Minimum number of trees 
10 inches or greater dbh 
per acre 
5 
7 
1 
4 
6 
Responses of Prai rie Ch ickens .to Habitat Manipulation r. L . Westemeier 
Analysis of the annual population changes of prairie chickens with estimated 
(r = U ;r P °; IT) Pa jL u Vear l at BOg °- a revea,ed a sl 9 n,f,cant correlation 
in llne of re 9 re ssion intersected the level of no chanqe 
.n the population at 45-4% nest success. Viewed another way, during 5 selected 
"T 36 7” the POpuUti ° n sh °“ ad Rennes rln 9 [n 9 
, ^ During 7 selected years when hatch success averaqed 47 97 
£ Hea'rs '^68 S r“ The dramati ‘ -creases 
I ’ '! ®' 7 !' occurred “ hen " e « success averaged 63 . 6 %. Thus, it appears 
rhiri™. 7 ? nests must approximate 50 % for a population of greater prairie 
chickens to maintain its numbers at Bogota. 
This summer 33 prairie chicken nests were found in 389 acres of sanctuarv 
grasslands at Bogota. Hatch success was 43 . 8 % (14 hatches among 32 nests of Y 
nown fate). Thus, 1979 is the 6th year among the past 7 years that hatch 
nrohnM $ ba '° W 5 he , critical level of 50%. Lever? nest successes 
search rrr eater ‘c 3 " ?! indicated above. Due to the inexperience of the 
! ha -hed nests were overlooked this summer. For example, 3 
prairie chicken hatches, 1 pheasant hatch, and 1 prairie chicken nest destroyed 
sLLar TIT 6 miSS6d bV tHe SSarch Crew in a 5 -acre fie,d on Jhe Yeat^r 
Sanctuary. These nests were found after the mixed prairie grasses and domestic 
TOre S diffic r !lTto d i and t ba 'h d '7 ^ bV thS ' eSSee - itched nests are generally 
. ftpn ? u 5 to ,ocate than destroyed nests because the egg shells in a hatch 
a . r ® ma,n ,n a "® at P lle fn the nest bowl. The shells f?om eggs destroyed by 
predators are usually scattered around the nest bowl and therefore are more visible. 
All unsuccessful nests found this summer were destroyed by predators 
at 1 Boqota tlT?* DeSpite the hi 9 hest Ph"»n? popLattoLLecord 
Bogota, there were no observed instances of nest parasitism by pheasants of 
prairie chicken nests in I979 (MWRL 22(8):3-4). y P f 
