Shorebird Use and Mortality at a Large Canadian Prairie Lake Impacted by Botulism

Publication Type:Journal Article
Year of Publication:2003
Authors:Adams, SG, F. Conly, M, Gratto-Trevor, CL, Cash, KJ, Bollinger, T
Journal:Waterbirds: The International Journal of Waterbird Biology
Date Published:2003
ISBN Number:15244695
Keywords:Calidris, Calidris alba, Calidris minutilla, Calidris pusilla, Ereunetes albus, Ereunetes minutillus, Ereunetes pusillus, Erolia minutilla, Limnodromus, Limnodromus griseus, Limnodromus scolopaceus, Recurvirostra, Recurvirostra americana, Recurvirostra avosetta, Recurvirostridae, Scolopacidae, Tringa, Tringa melanoleuca, Xenus, Xenus cinereus
Abstract:We surveyed the shoreline of a large terminal lake in southern Saskatchewan (Old Wives Lake) for sick or dead birds and estimated shorebird numbers during avian botulism outbreaks. Nearly double the number of shorebirds were present in 1999 compared with 1998. The most commonly observed shorebirds in both years were the Short-billed Dowitcher (Limnodromus griseus) and Long-billed Dowitcher (L. scolopaceus). Water levels were monitored, revealing a greater drawdown effect in 1998. Small species (e.g. Least Sandpiper (Calidris minutilla), Semipalmated Sandpiper (C. pusilla), and Sanderling (C. alba)) were much more common in 1998. Much of the data that exist on shorebird mortality during botulism kills is in the form of unpublished annual agency clean-up reports. These reports suggest that the American Avocet (Recurvirostra americana), yellowlegs (Tringa melanoleuca and T. flavipes), and the small Calidris sandpipers are the most commonly affected species. We suggest some biases inherent in these cleanup efforts that may unintentionally underestimate mortality due to botulism in some species of shorebirds. At Old Wives Lake, the most frequently affected shorebird was the Semipalmated Sandpiper (14) in 1998, and the American Avocet (5) in 1999. This study suggests that feeding habits may influence a species' susceptibility to botulism, namely those species that feed near the surface of the substrate are more prone to ingesting the botulinal toxin than those species which probe deeply in the sediment. There is also evidence suggesting that the intensity of the avian botulism outbreak affecting waterfowl may dictate the intensity of the shorebird botulism dieoff.
Short Title:Waterbirds: The International Journal of Waterbird Biology
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