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dc.contributor.authorDuBour, Adam J.
dc.descriptionThesis (M.S.) University of Alaska Fairbanks, 2019en_US
dc.description.abstractUnderstanding how patterns of food resources influence the behavior and fitness of free-living animals is critical in predicting how changes to such resources might influence populations. The boreal region of North America is relatively undeveloped and contains abundant freshwater lakes and wetlands. These largely pristine and stable habitats harbor high densities of aquatic invertebrates, which are a critical food source for the numerous waterbird species that breed in the boreal. Invertebrates are of particular importance for the optimal growth and survival of waterbird chicks. However, observations of long-term change to boreal aquatic habitats and their invertebrate populations associated with a warming climate has been implicated in the declines of some boreal breeding waterbirds, such as the lesser scaup (Aythya affinis). Lesser scaup are known to feed extensively on amphipods, a freshwater crustacean; however, ducklings have been shown to have a diverse diet. Our goal was to use the naturally occurring heterogeneity of aquatic invertebrates across boreal lakes within the Yukon Flats National Wildlife Refuge in interior Alaska to better understand how changes in invertebrate prey resources might affect diet selection and growth in lesser scaup ducklings. First, we used a stable isotope approach to quantify the variation in the trophic niche within our population of ducklings. We found that as a population, lesser scaup ducklings consume a variety of aquatic insects, crustaceans and mollusks, and that variation in the population diet is largely attributable to variation in diet between birds from different lakes with different invertebrate communities. Second, we used the same habitat heterogeneity to examine how gradients of invertebrate abundance relate to the growth of ducklings. We observed that lesser scaup ducklings experienced reduced growth rates in lakes that had little to no amphipods. Taken together, these results suggest that while lesser scaup ducklings are a flexible consumer that can adapt to changes in invertebrate populations, ducklings may face negative fitness repercussions when consuming prey other than amphipods.en_US
dc.description.sponsorshipAlaska Science Center, U.S. Geological Survey; Yukon Flats National Wildlife Refuge, U.S. Fish and Wildlife Service; and the Angus Gavin Memorial Migratory Bird Grant-University of Alaska Foundationen_US
dc.description.tableofcontentsChapter 1 General Introduction -- Chapter 2 The Role of Habitat Heterogeneity in Intra-Population Niche Variation in a boreal waterbird chick -- Chapter 3 Growth of Juvenile Lesser Scaup Across a Gradient of Prey Abundance in a boreal wetland basin -- Chapter 4 General Conclusions -- Appendix.en_US
dc.subjectlesser scaupen_US
dc.subjectYukon Flats National Wildlife Refugeen_US
dc.titleFeeding ecology of scaup ducklings across a heterogeneous boreal wetland landscapeen_US
dc.identifier.departmentWildlife Biology and Conservation Programen_US
dc.contributor.chairLindberg, Mark
dc.contributor.chairGurney, Kirsty
dc.contributor.committeeHundertmark, Kris

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  • Biological Sciences
    Includes WIldlife Biology and other Biological Sciences. For Marine Biology see the Marine Sciences collection.

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