saw this bird eating mouse, blue everywhere, wings legs, never seen something like it. Did an internet search can't find a juvenile anything blue. Bim in northern NJ.
Great Blue Heron
A gigantic Mountain Bluebird
The problem with eyewitness testimony is that eyewitnesses are generally really poor at it. There is an extensive -- and I mean EXTENSIVE -- literature on the fallibility of eyewitness reports. Our brains are incredibly good at MIS-interpreting information. There are no bird species that occur regularly in New Jersey that are entirely blue. Mountain Bluebird has occurred, but it eats mice even more infrequent