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Distribution and foraging patterns of common loons on Lake Michigan with implications for exposure to type E avian botulism

Journal of Great Lakes Research

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https://doi.org/10.1016/j.jglr.2018.02.004

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Abstract

Common loons (Gavia immer) staging on the Great Lakes during fall migration are at risk to episodic outbreaks of type E botulism. Information on distribution, foraging patterns, and exposure routes of loons are needed for understanding the physical and ecological factors that contribute to avian botulism outbreaks. Aerial surveys were conducted to document the spatiotemporal distribution of common loons on Lake Michigan during falls 2011–2013. In addition, satellite telemetry and archival geolocator tags were used to determine the distribution and foraging patterns of individual common loons while using Lake Michigan during fall migration. Common loon distribution observed during aerial surveys and movements of individual radiomarked and/or geotagged loons suggest a seasonal pattern of use, with early fall use of Green Bay and northern Lake Michigan followed by a shift in distribution to southern Lake Michigan before moving on to wintering areas. Common loons tended to occupy offshore areas of Lake Michigan and, on average, spent the majority of daylight hours foraging. Dive depths were as deep as 60 m and dive characteristics suggested that loons were primarily foraging on benthic prey. A recent study concluded that round gobies (Neogobius melanostomus) are an important prey item of common loons and may be involved in transmission of botulinum neurotoxin type E. Loon distribution coincides with the distribution of dreissenid mussel biomass, an important food resource for round gobies. Our observations support speculation that energy transfer to higher trophic levels via gobies may occur in deep-water habitats, along with transfer of botulinum neurotoxin.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Distribution and foraging patterns of common loons on Lake Michigan with implications for exposure to type E avian botulism
Series title:
Journal of Great Lakes Research
DOI:
10.1016/j.jglr.2018.02.004
Volume:
44
Issue:
3
Year Published:
2018
Language:
English
Publisher:
Elsevier
Contributing office(s):
Upper Midwest Environmental Sciences Center
Description:
17 p.
First page:
497
Last page:
513
Country:
United States
State:
Michigan, Minnesota, Wisconsin