Resource partitioning among five species of waterfowl (Anas spp.) at an autumn migratory stopover: Combining stable isotope and mercury biomarkers.

• Main Authors: Asante, Christian K., Hobson, Keith A., Bond, Alexander L., Jardine, Timothy D
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2017
• Subjects: Anas acuta
• Online Access: http://hdl.handle.net/1807/76849; http://www.nrcresearchpress.com/doi/abs/10.1139/cjz-2016-0063

The Saskatchewan River Delta (SRD) is North America’s largest inland delta and an important stopover site for waterfowl in the Central Flyway. However, little is known about their basic feeding ecology at this site and how species segregate or overlap in resource use. We used stable carbon (δ13C) and nitrogen (δ15N) isotopes and mercury concentrations ([Hg]) in liver tissue to trace use of local nutrient sources by five waterfowl species and tested for differences in diets among species, sexes and age groups. Macrophytes were the dominant food source for Northern Pintail (Anas acuta Linnaeus 1758) and American Wigeon (A. americana Gmelin 1789) with median proportions of 0.86 and 0.98, respectively. There was also evidence of partitioning of resources, as Blue-winged Teal (A. discors Linnaeus 1766) and Green-winged Teal (A. carolinensis Gmelin 1789) consumed invertebrates, as did a subset of Mallards (A. platyrhynchos Linnaeus 1758), suggesting that these birds might minimize competition for resources during the short staging period in the SRD when waterfowl densities are high. Other isotopes or tracers, such as [Hg] that varied among sources (0.03 to 0.20 µg/g dry weight) and waterfowl species (0.22 to 3.19 µg/g dry weight), can be used for further refining dietary estimates. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.