Thank you for the information. I don't have a feeder camera, and my birds scatter if I even enter the kitchen to look out the window. I suspect it's because a huge Cooper's Hawk has been killing my Mourning Doves, Blue Jays, and possibly my woodpeckers. They are understandably nervous about approaching my feeders with no nearby cover. At any rate, I don't think I would spot a sick bird. With the temperature ranging from minus 13 to plus 15 Fahrenheit, and a severe back injury, I can't commit the time to keep wiping stuff down with bleach. I get back spasms. I generally brush the frozen poop off the deck, and pick the frozen poop out of the open feeders with a putty knife. I really care about the birds, and hope my back finally recovers so I can be a better caretaker for them. In the meantime though, I suspect the frigid temps and hawk are bigger threats than communicable diseases. But I may be wrong. I get very few House Finches or Pine Siskins.