Dive characteristics of Common Loons wintering in the Gulf of Mexico and off the southern U.S. Atlantic coast

Journal of Field Ornithology
By: , and 

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Abstract

Common Loons (Gavia immer) winter primarily in marine coastal areas and utilize a forage base that is poorly defined, especially for offshore areas. Information on dive activity is needed for describing foraging strategies and for inferring prey distribution. Archival geolocator tags were used to determine the wintering locations and dive characteristics of adult Common Loons captured and marked on breeding lakes in Minnesota, Wisconsin, and the Upper Peninsula of Michigan. Among loons that completed fall migration, most wintered in the Gulf of Mexico, with smaller proportions wintering off the southern Atlantic Coast or impoundments in the southeastern United States. Adult Common Loons tended to occupy offshore areas of the Gulf of Mexico and the Atlantic Ocean and, on average, spent about 60% of daylight hours foraging. Dive depths were as deep as 50 m (Gulf of Mexico) and dive characteristics indicated that loons were primarily foraging on benthic prey. Total dive duration, time at maximum depth, and post-dive surface intervals increased with dive depths among wintering Common Loons. Our results are expected to contribute to the understanding of the wintering ecology of Common Loons and be useful in informing regional and national conservation planning efforts.

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Publication type Article
Publication Subtype Journal Article
Title Dive characteristics of Common Loons wintering in the Gulf of Mexico and off the southern U.S. Atlantic coast
Series title Journal of Field Ornithology
DOI 10.5751/JFO-199-940101
Volume 94
Issue 1
Year Published 2023
Language English
Publisher Resilience Alliance
Contributing office(s) Upper Midwest Environmental Sciences Center
Description 1, 11 p.
Country United States
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