True Metabolizable Energy (TME) is a measure of the assimilable energy (kcal) a food item provides a consumer and can be useful for wildlife managers to decide which plants to encourage/discourage when managing wetlands for waterfowl. The current availability of TME estimates limit the understanding of the impacts habitat management decisions have on the energetic carrying capacity of wetlands. Furthermore, TME values for specific food taxa may differ among waterfowl species and such differences are important for determining appropriate management strategies. Prior TME research prioritized food items most commonly found in waterfowl diets and mostly focused on a single waterfowl species, leaving a gap in information on moist-soil seeds considered undesirable or invasive by wetland managers. Therefore, we will estimate TME values of several moist-soil seeds considered by waterfowl managers as desirable (e.g. Polygonum lapathifolium, Cyperus erythrorhizos and Leptochloa panicoides) and several considered to be undesirable (e.g., Sesbania herbacea, Polygonum hydropiperoides, Sida spinosa, Cyperus iria, Sphenocela zeylanica) within wild-caught mallard (Anas platyrhynchos), northern pintail (A. acuta), green-winged teal (A. crecca). From December 2019 to March 2020, we completed 7 feeding trials and from October 2020 to April 2021 we plan to run 17 feeding trials using 8 seed and 3 duck species during the non-breeding period. Each 48-hour trial included 24 hours of fasting to clear the birds’ digestive tracts, precision feeding a known mass of a single food item, followed by a 24-hour period of excreta collection. Individual ducks were used in multiple trials with different seed species but were given a >14-day respite between trials. Our results will be used to support conservation planning models to refine waterfowl objectives stepped down from the North American Waterfowl Management Plan to better inform waterfowl conservation planners and wetland managers throughout the Mississippi Flyway of the United States.
|Title of host publication
|81st Midwest Fish and Wildlife Conference
|Published - 2021