A mea culpa is in order before discussing sea duck trolling. I use plastic eider decoys in my old age, so much lighter and easier to manage than wood and cork. And I don't cry when one gets shot.
The sea ducks (scoters, oldsquaws and eiders) are well known for not being particularly boat shy. Especially scoters, who sometimes come close enough to scoop with a net. In areas with current, and deep water, we have always used longlines which we deploy by motoring slowly and then towing them into position to anchor or tie off on shore. We've noticed many times how birds will decoy when the rig is in motion, I guess it's a little like a jerk string. What is particularly effective, and the reason for mention of wood decoys, is that heavier wood decoys tend to submarine when towed. That diving and resurfacing action is like a magnet, the birds must see that as a flock feeding. Of course there's no shooting involved so the birds would sometimes light, fall behind as you move away, get up and light again. Again, especially scoters, the immature coots are oblivious like kids texting.
I don't know if I'll ever get the chance to travel to Greenland or Alaska for a King Eider hunt, but have always wanted to. In all the years I've hunted them we've only gotten a couple (or three?) all by sheer luck. They are a pretty bird.
