Monitoring the impacts of the Gordon C. Leitch oil spill on the breeding bird populations

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ROBERGE, B. AND G. CHAPDELAINE. 2000. Monitoring the impacts of the Gordon C. Leitch oil spill on the breeding bird populations of the Mingan Archipelago National Park Reserve (QC), Canada . Technical Report Series No. 359, Canadian Wildlife Service, Quebec region, Environment Canada, Sainte-Foy, xi+21p.

ABSTRACT

Soiled Eider duck
© Parks Canada / H. Lauzière / P 01 12 21, 1999

A monitoring program has been undertaken by Parks Canada and the Canadian Wildlife Service to evaluate the impacts of the Gordon C. Leitch oil spill, in Havre-Saint-Pierre in 1999, on the breeding bird populations of the Mingan Archipelago National Park Reserve (Gulf of St. Lawrence (QC), Canada). The three breeding bird species studied are the Common Eider ( Somateria mollissima ), the Black Guillemot ( Cepphus grylle ), and the Bald Eagle ( Haliaeetus leucocephalus ). The surveys were completed to provide a means of comparing the status of these bird populations on islands located inside and outside the contaminated area, both before and after the oil spill. The Gordon C. Leitch oil spill does not seem to have brought on noticeable impacts on the reproductive potential of the breeding bird populations of Minganie. The breeding population of Common Eiders on the islands located within the contaminated area has decreased from 1861 pairs in 1998 to 1707 in 1999 following the oil spill. The differences in the number of Eider nests on the islands surveyed ("test" and control islands), both before and after the oil spill, are not significant. Common Eider productivity in the Mingan Archipelago did not significantly differ between 1998 and 1999. The slight variability observed between 1998 and 1999 may result from natural processes or variations in the sampling method. The breeding Black Guillemot population of the Mingan islands does not seem to be visibly affected by the oil spill. On the islands that were contaminated with hydrocarbons, the Guillemot population has increased by 60% that is, from 32 pairs in 1994 to 54 pairs in 1999. The Bald Eagle population in the Mingan Archipelago seems stable, with four (4) nesting pairs in both 1998 and 1999. In 1999, the mean productivity of Bald Eagles, with two (2) eaglets/nest, suggests a healthy population. All in all, the Gordon C. Leitch oil spill may have caused the death of an estimated 211 to 777 breeding birds or 0,4 to 1,6% of the total number of breeding seabirds in the Mingan area. Protective measures are recommended in order to mitigate the effects resulting from the oil spill and to prevent as well as limit the impacts of such incidents.

This report is available at the Regional Library of Parks Canada in Quebec.