Blue Jays are supposed to eat nuts, seeds, buds, and berries. Any school child can tell you that. This one, however, appears to have killed a bird of similar size and is having it for breakfast - on my back porch. I was having eggs for breakfast, so who am I to be anthropomorphizing?
One spring, years ago, I watched a female pheasant chase a field mouse out of the tall grass, pounce on it, and eat it whole: later reading that such opportunistic meat eating had been observed in female pheasants, during nesting season.
This Blue Jay eating a recently-killed bird took me by complete surprise, however. Had it gone predatory to expand it's dietary footprint in the same manner of the pheasant? Or to reduce the success of a competitive species? Or, is lack of some normally available food during nesting season - yes I am speculating about climate change here - part of the reason the Killer Blue Jay has appeared on my deck?
Had I not seen it with my own eyes, I'd have blamed the neighbor's cats.