Sex Ratio: Egg Fertility Relationships in the Ring-Necked Pheasant

tion showing the extremes of spring sex ratios which can be tolerated among pheasants (Phasianus colchicus torquatus) without reducing the productivity of the species. Valid information on sex ratio requirements would enable game administrators to establish open seasons and bag limits on a sounder basis. Some data bearing on this problem have been accumulated by the Michigan Department of Conservation in connection with a Pittman-Robertson pheasant research project (7-R) conducted on the 8,400 acre Prairie Farm (Saginaw County) and at the Rose Lake Wildlife Experiment Station (Clinton and Shiawassee Counties) during the past six years (Pittman-Robertson project 2-R), and in connection with earlier investigations at the Kellogg Bird Sanctuary (Kalamazoo County). Field Observations: On the heavily hunted Prairie Farm 75 to 90 per cent of the cocks are removed during a hunting season and the spring sex ratios during the years of the study averaged one cock to seven hens. It was not uncommon to observe nine or ten hens with a male bird, and in a few instances the ratio was even greater. In the last week of April, 1940, G. A. Ammann observed a cock on a crowing area with 16 hens and a year later another was accompanied by 18. Although it is possible that these birds may have been part of winter flocks it is rather doubtful, since nests were located in the first and second weeks of April each year, a good indication that hen pheasants were in breeding condition at this early date.