There are various account of bird populations crashing in the US, Germany and France, but what about individual birds disappearing while being observed?
"Description: I live in Everett, WA by the naval base. Four days ago I watched 50 to 75 birds vanish at the same spot above the boat. They flew one by one and poof. Gone. This was about over an hour before sunset.
Witness Response to Investigator Questions: It was partly cloudy and then like poof, the birds were there one second and gone the next. One by one they vanished in the exact same spot. This happened at Everett Naval base. "