The Importance Of Eurasian Milfoil (Myriophyllum Spicatum) As A Waterfowl Food

The primary objectives of the study were to determine and document waterfowl use of Eurasian milfoil in the vicinity of a new outbreak near Back Bay and Mackay Island National Wildlife Refuges in Virginia and North Carolina. Digestive tracts were collected in the vicinity of Back Bay, Virginia, and Currituck Sound, North Carolina, during the 1968-69, 1969-70 and 1970-71 hunting seasons. Examinations of 170 waterfowl digestive tract contents included 27 Canada geese, 74 dabbling ducks of six species, 38 diving ducks offour species and 31 coots. Analysis revealed that: 71.8 percent contained Eurasian milfoil, 84.7 percent held other foods, 13.5 percent had milfoil as the only food, 27.1 percent had other foods but no milfoil and 1.8 percent had no food. Quantitative analysis showed that the content of all digestive tracts was 43.9 percent grit, 18.3 percent Eurasian milfoil and 37.8 percent other foods.When considering food only in the 170 tracts of 12 waterfowl species, milfoil comprised approximately one-third of the volume. Highest milfoil use was noted in scaups, followed in order by gadwalls, widgeons, Canada geese, redheads, pintails, green-winged teals, ruddy ducks, black ducks, coots, mallards and canvasbacks. Natural foods led the "other foods" category and were headed by pondweeds, widgeongrass, southern naiad, wild celery plants and seeds, and by seeds from the family Cyperaceae.

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