i can't help with the tips about EE, but i hunt Sauvie Island alot and i am sure that hard pressured ducks act pretty much the same most places.
It is in my limited experience (really) that when i am getting ducks to look, but not finish, it is usually due to one or more of the following things.
#1 - the ultimate killer...movement. no, not that wing flappy thingy or your jerk spreader out there in the water. you, your partner, your dog..don't just cut down on your movements in the blind. stop them completely. is your arm moving all over the place pulling that jerk cord? are you shifting around, moving your feet, and reaching for your gun? is your hunting partner pointing at the birds and telling you they are coming in? (we know YOU wouldn't do such a thing.
#2 - Noise. speaking of your hunting partner pointing at birds. did he just announce in a normal conversational tone that they were coming in? voices cary a long way...birds can and will flare at, "HEY JOE!! BIRDS ON YOUR LEFT!"
#3 - Concealment. can you see the birds? if so, they can see you too. while it is basically impossible (or at least really impractical) to stay 100% concealed, you can do a few things to help out. stay low in the blind and keep in close to the cover to help blend in. if you sit back 5 feet from the blind you will stick out like tits on a boar. also, try not to stare at incoming birds. it has been suggested by people much smarter than i that animals lower on the food chain can pick out a pair of eyes staring at them as if they are next up on the menu. instead, take quick glances at incoming birds and instead of staring at them, pick out spots along their path and adjust your vision inward as they approach. ie: spot them at 100 yards so look in about 80. spot them again at 80 and look in around 60..spot them at 60 and watch the area around where they should finish out...when you see them this last time, take 'em.
#4 - They just don't like you. sometimes it happens. maybe they are trying to land, but the position of your dekes is actually keeping them out. sometimes heavily pressured birds won't fly over dekes. if your dekes are keeping the birds from making a natural approach, they may just flare off and find someplace else they like better. try openeing up your landing zone to accomodate their flight paths. also, you can space out your dekes to allow them more places to land. if i am using this last tactic i will cut down to about 2 dozen dekes and space them at least 2 feet apart.
#5 - Calling. try not calling while the birds are flying at you. if they turn, hit them with a SOFT quack or chuckle....hit them again with a comeback if they keep leaving. if they turn back in...stop calling.
anyway, these are a few things that i have learned the hard way. sometimes it is one of these things, sometimes it is a combination of these things, and sometimes i sit in my blind scratching my head in wonder at why those silly birds with brains the size of BB's won't land in my spread. :hammering:
Friends Don't Let Friends Shoot Mossbergs.