t £M\—«*Y 
NATURAL HISTORY SURVEY 
MONTHLY WILDLIFE RESEARCH LETTER 
Illinois Federal Aid Project W- 66 -R 
Department of Conservation and Natural History Survey, 
Glen C. Sanderson and Eva Steger, Editors 
MAY 91979 
LIBRARY 
Cooperating 
Urbana, Illinois 
Apr i 
1979 
Vol. 22, No. 4 
Manipulati on of Pheasant Habitat „ 
-- r. e. Warner 
In last month's newsletter (MWRL 22(3):1), trends in the abundance of 
5 c J? an . tS ° n 5 areas--the Ford County Management Unit (FCMU), Sibley Study Area 
(SSA), Anchor, Harwood, and Prairie Green—were reviewed relative to winter- 
storm-related mortality noted in January 1 977 and during the winter of 1977 78 
Documented mortality from exposure to winter storms provides opportunity for 
dur nn r 9 h the ' mportan ;' e of wood V v e 9 e tation to survival of ringneck populations 
during such severe weather conditions in east-central Illinois. 
In January and February 1979, existing woody vegetation was recorded on 
t mapS .° f 1? ar ? a ‘ °" each are ^ 9 "*unit. were delineated? 
comprised of 4 sections (2 x 2) per subunit; a cock call count station was 
located at the center of each subunit. 
Two indices were applied to measure woody vegetation on the subunits: 
LLri ‘ n ?* r me ^ su rement was made of occasional or continuous trees and shrubs 
o? a onn a -r y - V T tat i°? ?" the areas exists in «rlp. as hedgerows 
or along tributaries), and ( 2 ) a circle with a 1 -mile radius was inscribed on a 
° f ,“ Ch subuni t; the number of intersections of the circle and woody 
vegetation was then tallied. ^ 
Linear measurements of woody vegetation on the areas (summation of 9 sub- 
th" FCMu" SS r A ea) A t 0 h ta 1 ed M ,5 ‘ 3 ^ ,9 ’ 87 ' 22 *° 3 ' 3KI6 ' 3nd 4 7*'3 kilometers^ 
of i nterser Hon^ nC f ° r ^ " arvJOOd ’ a ? d Prairie Green, respectively. The number 
41 for the FCMU \ ^ e 9 etat,on and circles totaled 1 3 , 16, 1 5 , 20, and 
41 for the FCMU, SSA, Anchor, Harwood, and Prairie Green, respectively. 
In next month's newsletter, declines in cock calls from 1976 to 1978 will 
be considered relative to indices of woody vegetation on each subunit. 
Ecology and Management of Sguirrels 
C. M. Nixon, 
L. P. Hansen 
n*rt; A Y nd,Cat * d ,ast month ' s newsletter, fox squirrels often select 
-- " pec,es of tree as sites for leaf nests. To determine what tree 
character! s t,cs attract fox squirrels, we looked at some of the physical 
attributes of the most suitable trees. 
We compared the number 
6-10 and 12 - 20 + inches dbh, 
of leaf nests built in 2 size classes of tree, 
and found larger trees had significantly more leaf 
