Not to be a Debbie Downer, but quite often these "tame" birds, especially those in the finch family, are actually sick. There is an outbreak of Salmonellosis this year among siskins, finches, and crossbills. It seems to have subsided in some areas but not all. Last week in Idaho City I visited a feeder setup and saw a number of infected Cassin's Finches, so it is still going around.
You can tell infected birds because they will be slow to fly away, not-wary of people, may have fluffed up feathers and look "fatter" compared to other individuals of the same species. The birds often sit on the feeder and eat voraciously until the late stages of the disease.
They may also be more "blinky" or sleepy, and may be unable to fly or have weak flight. Up close if the disease is severe you will hear clicking or scratchy labored breathing.
In this case it certainly sounds like you have sick birds. It is important to take your feeder down and bleach it with a 10% bleach solution. Leave the feeders down for at least two weeks to allow sick birds to disperse. When hanging feeders back up, be sure to watch frequently for sick birds and remove the feeders again if sick birds reappear. Even if no sick birds are spotted, continue to bleach your feeders with a 10% bleach solution at least once a week.
The sickness is spread through droppings so be sure to remove any dropping accumulations by raking the ground, and remove any accumulated seed on the ground. Bird baths and flat platform feeders also accumulate droppings and should be removed.
Of note, just because you have sick birds on your feeders doesn't mean it's your fault. Even if you have the cleanest feeder around, if even one of your neighbors has a poorly cleaned feeder, the disease will continue to spread. All we can do is remove our feeders when we spot sick birds, and help spread the word to others in the area to take their feeders down too.
Intermountain Bird Observatory