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V. 3, ri6 , I 3* 
MONTHLY wildlife research letter 
Department of Conservation and Natural History Survey, Cooperating 
T. G. Scott, Editor 
Urbana, Illinois 
December, 1960 
Vol. 3, No, 12 
W-30-R-14 R..F. Labisky, R. I. Smith 
Pheasants have been trapped on the Sibley study area during fall and winter 
for the past 5 years through use of the night-lighting technique. Each bird was 
marked with a numbered back-tag and released at the trapping site. Three hundred 
forty-eight or 24,3 per cent of the 1,435 tags used during the 4-year period, 1956- 
59, have been recovered as mortalities, resulting from hunting, farming operations, 
road kills, predation, and other natural crises. The date or estimated date of 
death was recorded for each tag recovered. The data in Table 1 represent mortality 
of pheasants marked within a specific calendar year, but without special reference 
as to what specific date the birds were marked within the year. 
Life expectancy of marked hens was greater than that of marked cocks, assum¬ 
ing that tag-recovery rates reflect mortality rates. Only a small percentage of 
the marked hens survived to the third year following the date of tagging. Even 
though the cock segment of the population exhibited a more rapid turnover, the per¬ 
centage of cocks removed by hunting each year (based on pre- and post-hunting 
season sex ratios) did not show a direct relationship to the turnover of the cock 
segment of the population. 
Table 1,~ A comparison of pheasant back-tag recovery rates and the per cent 
of cocks harvested on the Sibley study area, 1956 through I960, 
Per cent of Sibley Tag recoveries Per cent of tag recoveries 
area cocks removed as of Jan, 1, occuring each year 
by hunting* 1961 -— 
Year 
1956 
1957 
1958 
1959 
1960 
1956 
59.4 
c? 
63 
79.4 
19.0 
0.0 
1.6 
0.0 
o 
20 
35.0 
50,0 
5.0 
5.0 
5.0 
1957 
12.4 
s* 
52 
73.1 
21.2 
3.8 
1.9 
$ 
31 
48.4 
41.9 
6.5 
3.2 
1958 
44.0 
c? 
85 
97.6 
2.4 
0.0 
9 
31 
41.9 
35.5 
22.6 
1959 
52.5 
& 
39 
100.0 
0.0 
9 
27 
55.6 
44.4 
*This percentage 
obtained from 
pre- 
and post- 
hunting 
season : 
sex ratios 
• 
7TATURW 
