Diseased Bird: Sick goldfinch (only 1 sick bird seen)

A sick goldfinch showed up today – it was very lethargic and puffed up. Didn’t fly away when I approached. It was sitting in my tray feeder so I was able to get a picture. It has a strange, white, flaky mass around its beak. The eyes may be swollen but hard to tell in photos and I couldn’t get close enough. I took down my feeders and emptied all water stations. Swept up around all areas. Feel bad for all the other birds now sitting and waiting for their seed to come back!