LE3 .A278 1973

1973

Austin-Smith, Peter

Acadia University

Master of Science

Masters

Biology

Biology

Investigations were conducted in the Liscomb area of Nova Scotia's eastern shore between April 1970 and August 1971. The objectives were to determine duckling mortality rates, brood movement and general brood ecology of the common eider (Somateria mollissima dresseri) by observing marked and unmarked ducklings and adults. The mortality rate of ducklings from hatching until five weeks of age was 75.5 per cent. No mortality was recorded for ducklings older than five weeks. Eider broods moved from the nesting island to the mainland coast directly upon leaving the nest. They remained in isolated beys and inlets for five to seven weeks before moving to off-shore shoals. The diet of eider ducklings was 99.4 per cent animal foods. The species of mollusc in greatest abundance in an area was the main food of ducklings in that area. The formation of creches was of no survival value to the ducklings and the assistance of broodless females or "aunts" was ineffective in preventing duckling losses to gulls under adverse sea conditions.

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