Bald Eagle 1, Barrow's Goldeneye female 0

I just witnessed the local Bald Eagles take a female Barrow's Goldeneye from the Slocan Pool. First, one adult Bald Eagle swooped a group of Goldeneyes and then a second eagle joined in. They spent about 10 minutes swooping over the group until one duck was separated from the rest. They swooped low over her for another 5 minutes and then made two attempts to catch her. The second attempt was successful. The eagle sat in the water, made one attempt to fly off with the duck, failed, and then after about 10 minutes swam to the shore and proceeded to feed on the duck. The second eagle had flown to a nearby snag earlier and called occasionally.  After I left, I noticed another adult Bald Eagle fly and land near the feeding eagle.  My neighbours Al and Val, who have a view of the Slocan Pools from their house, also came down to watch the drama unfold. According to one website I checked an adult eagle needs to eat .5 to 1.5 pounds every day. Sibley's Field Guide states that Goldeneyes weigh 2.1 pounds, therefore, an eagle  needs to catch a duck almost every day and more when feeding nestlings!