Are blue jays known to prey on other birds? I've found that they are known to raid nests of eggs and young, but have not found any evidence of them actually preying on other birds.
Background: A few years ago while raking leaves this time of year (late Oct/early Nov) the head of a house sparrow fell on me. I looked around in the spruce tree I was under and saw a blue jay eating the rest of the house sparrow. This was approximately 10 feet from my bird feeders. I can't say that it wasn't dead beforehand, but it's proximity to the feeders made me wonder.