A Biotelemetery Study of Survival of Pen-Reared Pheasants Released in Selected Habitats

Juvenile game-farm pheasants (Phasianus colchicus) equipped with radio transmitters were released in optimal and marginal habitats in southern and central Minnesota, respectively. The releases were intended to study survival rates and causes of mortality of pheasants raised and stocked in the Minnesota day-old-chick program. Of 74 birds which were tracked during the 28 days following their release, 60 (81 percent) died. Causes of death during the 28 days post-release, included predation (55), unknown (3), starvation (1), and farm machinery (1). The major predators included red-tailed hawk (Buteo jamaicensis), great-homed owl (Bubo virginianus), red fox (Vulpes fulva), and mink (Mustela vison). There was no difference in survival between birds released on the two habitat types. Survival of sexes was similar. Hens weighing less than the median weight on release survived better (P < 0.01) than hens weighing more than the median weight. No such weightrelated differential mortality was observed for cock pheasants. Fox predation was higher than scat and digestive track analyses of fox food habits would have indicated. Game-farm birds dispersed very slowly and appeared to exploit habitat edges. Factors preventing their survival appeared to be concerned with deficiencies in the behavioral repertoire. The fate of game-farm pheasants released into the wild has been the subject of considerable research and speculation (Allen 1956). Because it is difficult to locate either live or dead birds in the field, few studies have concentrated on the survival of subadult game-farm pheasants between the time of release and the hunting season. However, the development of bio-telemetry techniques has made it possible to obtain large quantities of detailed information on the activity and mortality of radio-tagged animals (Marshall and Kupa 1963, Mech 1967). This paper reports survival rates and mortality factors of juvenile game-farm pheasants equipped with miniature radios and released into optimal and marginal habitats in Minnesota. The birds were monitored with portable receivers and where possible, the specific mortality factor was identified for those recovered at death. 1Present address: James Ford Bell Museum of Natural History, University of Minnesota, Minneapolis, Minnesota 55455. This investigation was supported by PHS Training Grant No. 1 TO1 GM01779-01 from National Institute of General Medical Sciences, U.S. Atomic Energy Commission Contract AT(11-1)-1332 (Publ. COO1332-41), and the Minnesota Conservation Department, Division of Game and Fish. We appreciate the aid of V. B. Kuechle, M. E. Sunquist, S. G. Curtis, B. L. Bonde, E. D. Kopischke, R. N. Johnson, and R. J. Schuster. W. H. Marshall and A. B. Peterson made the facilities of the Cedar Creek Natural History Area available and E. J. Cushing, J. M. Beer, and A. B. Sargeant provided helpful suggestions to improve the