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UBC Theses and Dissertations

Factors affecting orchard pheasant populations in the Okanagan Valley of British Columbia, with special reference to orchard insecticides Rye, Darrell

Abstract

Pheasant chicks were tested under both field and laboratory conditions for susceptibility to both inhalation and ingestion of DDT, parathion, methoxychlor, aramite, sulfanone, and #4049 (an organic phosphate). An attempt was made to correlate chemical analysis for DDT in the tissues of dead birds with death from known amounts of DDT. The effect of concentrate spray machines as opposed to hand-gun machines was tested, and an attempt made to evaluate the factors controlling populations of pheasants in the Okanagan Valley, British Columbia. Both DDT and parathion were found to cause considerable mortality under ideal conditions, but it is thought that such conditions are seldom realized. In the field, parathion acts chiefly through inhalation toxicity, while the reverse is true of DDT. Concentrate machines apply only 30-40 percent as much insecticide to the cover crop in an orchard as do hand-gun machines. The increasing use of such machines may result in a decreased effect of poisons such as-DDT, which acts through ingestion; the finer mist produced by concentrate machines however, may enhance the effect of inhalation poisons such as parathion. Methoxychlor, aramite, sulfanone and # 4049 were found to be nontoxic to pheasant chicks in the concentration employed for the control of orchard pests. These materials are expected to replace DDT and parathion in the Okanagan Valley in the near future. The chemical analysis of dead birds for the presence of DDT has not proven satisfactory to date. The qualitative reduction of pheasant habitat in the Okanagan, as a result of intensive orchard cultivation, is believed to be the greatest single factor affecting pheasant populations in this area. Much of this intensive cultivation is due to the increasing use of sprinkler irrigation, permitting frequent mowing, discing, or other disturbance of the orchard cover crop.

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