Cynthia: You live at Jackson & Sheriden; I live at Jackson & Heberton. YOU are the one who stole my birds and I want them back! How many cardinals do you need?
 
Thanks for all the suggestions from the group. I'm thinking now it's the bird feeder after all. This morning I saw two birds (one a cardinal) on a plate of bird seed we put out almost two weeks ago. It had been covered with snow and ice that just melted the other night. So if they can come back for wet seeds, it's obvious they're not getting anything from the feeder. Last year our back yard was Grand Central Station for the birds.