This last week we have had a disease at the bird feeders.

Initially, I found a pine siskin sitting on the ground, directly underneath the feeder. He had his head tucked under his wing. I picked him up and brought him into the house. He died a few minutes later.
Over the next 24 hours, I found several dead pine siskins near the feeder. By the 4th bird, I realized they were experiencing some kind of plague. I googled "pine siskins, disease" and found that it was being witnessed all over Northern California, mostly at feeders. The disease is Salmonella. Pine siskins are the most susceptible bird species. So far, I haven't seen any other kind of bird that is sick.

Many of the ones that weren't dead would let me walk right up to them. They also flew into the window glass more frequently.

It is recommended that bird feeders be removed when this happens.

Terrible..