Vol . 9, No. 6 
Page 2 
Reverse ca 1 cul at i ons from the equation given above show that the area 
necessary to search for a 25% accuracy varies from 16 acres for a density of 4 
nests per acre to 128 acres for a density of £ nest per acre. Regardless of the 
density, a total of 64 nests in a cover type will give an accuracy of + 25 % with 
a confidence of 95 %. However, cover types which contribute relatively few nests 
to the total need not be estimated with the same precision as those contributing 
more nests; i.e., a 25% error for a cover type contributing 100 nests is more 
critical by far (+25) than a 50 % error for a type contributing 20 nests (+ 10 ). 
Table 1 shows that in 1964 strip cover and hay, each totalling about 40 acres, 
provided samples with an accuracy of + 0-5 nest per acre ( 25 %). In order that 
samples in hay be comparable to that in strip cover (the area of the latter is 
re atively constant from year to year) it becomes necessary to search at least 32 
acres of hay, if the nest density is 2.0 nests per acre. In order to allow for 
a lower nest density this year, 64 acres of hayfields have been selected at random 
over the study area for nest searches in 1966. The results are expected to provide 
an estimate of nest density in hayfields of the same or better accuracy as that 
in any other cover type. 
2. Manipulation of Pheasant Habitat 
G. B. Joselyn 
The density of pheasant nests on seeded roadside plots during 1963 was 3.1 
nests per acre in fencerows and 2.8 nests per acre in the remaining portions of 
he plots (Table 2); in 1964, the relative densities were reversed with 2-5 nests 
per acre established in fencerows and 4.0 nests in the remainder of the seeded 
roadsides. This high relative incidence of nests in that portion of the seeded 
roadsides outside the fencerows continues in 1965 with nearly three nests per 
acre compared to only one nest per acre in the fencerows. On the basis of these 
limited data ,t may be concluded that the quality of nesting cover in that portion 
of the seeded roadsides outside the fencerows has improved over the past 3 years 
relative to the cover in the adjacent fencerows. Therefore, a shift of nests back 
into the fencerows adjacent to the seeded plots in future years might indicate 
the beginning of deterioration of the seedings as quality nesting cover. 
On managed control plots there was a pronounced tendency for nesting to be 
concentrated in the fencerows during all 3 years, indicating that on these plots 
the preferred nesting cover was found in the fencerows. Thus, in spite of the fact 
that there was no mowing on the managed control plots, generally higher and denser 
cover was probably present in most fencerows than on the remainder of the plots. 
3* F actors . Influencing Distribution and Abundance of Pheasants W. L. Anderson 
Counts of the number of ruptured follicles found in ovaries of 13 hen 
pheasants collected during May 1 966 in Ford and Livingston counties suggest that 
the "average" hen in the better pheasant range began laying eggs about April 30 . 
The estimated dates on which laying began were arrived at by allowing 1.3 days 
eac e 99 (ruptured follicle) laid. Considerable variation occurred among the 
13 hens examined. The earliest estimated date on which laying began was April 18 
and the latest date was May 9 . Although the reasons for this variation are poorly 
understood, it seems likely that the age of the birds, their physical condition, 
