( 
MONTHLY WILDLIFE RESEARCH LETTER 
Illinois Federal Aid Project W-66-R 
Department of Conservation and Natural History Survey, Cooperating 
Glen C. Sanderson and Helen C. Schultz, Editors 
Urbana, Illinois 
December, 1976 
Vol. 19, No. 12 
Manipulation of Pheasant Habitat R* E* Warner 
In the 4 years (1973-76) in which pheasant nest studies have been con¬ 
ducted on the Ford County Management Unit (FCMU), an estimated average of 44 
percent of all successful nests on the area were hatched in seeded roadsides. 
Therefore, roadside mowing prior to the prescribed mowing date of 1 August can 
destroy or prevent the establishment of a substantial portion of pheasant 
nests in the FCMU and thus reduce the benefits that seeded roadsides afford 
the pheasant population. In view of early roadside mowing, the phenology of 
the hatch on FCMU roadsides is an important consideration. Approximately 12 
percent of the successful nests are hatched on FCMU roadsides by mid-June, 
81 percent by mid-July, and 97 percent by 1 August (Table 1). 
The percentage of roadsides mowed prior to the delayed mowing date of 
1 August has been emphasized as a relative index of roadside mowing patterns 
from year to year (MWRL 19(8):1)< These indices of mowing phenology, 1970-76, 
are listed in Table 2. Although supplying relative information regarding 
mowing patterns on the FCMU, these figures do not specify when roadsides were 
actually mowed. Determining more specifically than the 1 August figure 
(Table 2) when roadsides were mowed is significant because the nesting potential 
of roadside vegetation is diminished in direct accordance with how early road¬ 
sides are first mowed (Table 1). For example, mowing 15 July would not be as 
detrimental to overall nesting activities as mowing 15 June. 
In order to determine more precisely the extent to which annual variations 
in mowing affec . the potential of seeded roadsides as nes cover, a method of 
calculation was performed that accounts for the phenology of the hatch when 
roadsides were mowed annually and the amount of continued nesting activity 
that could have been expected if all roadsides on the FCMU were left unmowed 
through 1 August. For each 15“day period, 1 June-31 July, the percentage of 
nests hatched during the period (4-year averages for the phenology of hatch 
are shown in Table 1) was multiplied by the percentage of FCMU roadsides re¬ 
maining unmowed through that 2-week interval. The calculations performed for 
the periods were then summated for each year. This summation provided an 
index of the percentage of the potential nesting activity annually realized on 
FCMU roadsides (Table 2); the maximum potential of roadsides for nesting 
assumes that no roadside mowing occurred prior to l August. 
The calculations in Table 2 reveal that in years when early roadside 
mowing was relatively extensive, as in 1975 and 1976, recruitment to the fall 
_ pheasant population from hatched roadside nests was not curtailed as much as 
