Hello!
This is an American Goldfinch that appears to have something wrong with its eye. I’m not an expert in the matter, but this looks like avian conjunctivitis (or “House Finch Eye Disease”). Avian conjunctivitis is extremely contagious, and unfortunately there isn’t much you can do for this individual. It may recover from the illness, or it may not. Sick or injured birds are much more likely to get preyed upon. (I don’t believe there is current evidence to suggest that a predator (especially a non-avian one) could get sick from this)
That said, currently most advice out there suggests that the best thing you can do is not for this bird but for the others around it. Take down your feeders and clean them (we should all be doing this regularly!) Some advise leaving your feeders down for a few weeks - this gives time for the infected bird to either recover or die, while lowering the risk of exposing other birds. It is sad, but sometimes the best we can do is allow nature to take its course.
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