Common Redpoll

I have Redpolls again this year...somewhere around 20 or so.  A couple of years ago, I had hundreds that ate me out of house and home.  As with most of the birds this year, I'm having trouble getting the kind of pictures I what.  Since all the pictures are shot through a window, I'm thinking that this may be the problem.  The windows look fairly clean from the inside but outside you an see a super fine coating of dust deposited from all the winds that we get here by the lake.  Hoping for a warm day above freezing that I can get out to clean the windows on.