NON-HUNTING MORTALITY OF FLEDGED NORTH-AMERICAN WATERFOWL

A survey of nonhunting mortality of wild waterfowl was conducted by the Delta Waterfowl Research Station, Delta, Manitoba [Canada], 1963-65. Records of reported mortality (n = 2,108,880) for the period 1930-64 were assembled from open literature, unpublished federal reports and a questionnaire. Nonhunting mortality band recoveries (n = 25,817) for 1930-63 were analyzed. Data were compiled on mortality from collisions, weather, predation, pollution, diseases, poisions and micellaneous factors. Collision mortality (n = 3015) was 0.1% of the total sample and was reported commonly from the Central Flyway. Collisions with utility wires and automobiles were the most frequent causes of mortality. Weather-related mortality (n = 158,723) was attributed to 7.4% of the total sample. Hail was the most important factor during summer. In other seasons various factors operated in concert with cold weather. Predation (n = 2621) accounted for 0.1% of the total mortality reported. Losses appeared to be of similar magnitude in all flyways and peaked during summer. Mortality from pollution (n = 13,944) was 0.6% of the total sample. Losses were concentrated on the Atlantic coast and were proportionally heavier among diving ducks (Aythyinae). Mortality from disease (n = 1,873,970) was 87.7% of the total mortality studied. Losses were most prevalent in the Central and Pacific flyways during summer and fall. Mortality from miscellaneous causes (n = 82,424) was 3.8% of the total sample. Losses were confined largely to the Mississippi Flyway and to the summer-fall period. The seasonal losses peaked during winter and spring.