I have witnessed this!
A few years ago, I was in the back yard cleaning the muck out of the
goldfish pond. I had a border collie (that we lost just over a year
ago to an intranasal tumor) and he HATED Magpies. He must have done
something to a Magpie in the yard because I heard the birds going
absolutely CRAZY. I left the pond (and all of the joy cleaning the
muck entails) and walked to the back of the yard. There, by the
fence, was a Magpie lying on the ground. There must have been 20 other
Magpies perched on the fence cawing. They would fly down in pairs, or
alone, and pull on the feathers and try to "wake" the dead Magpie up.
It was really sad, and very touching. I went and buried the Magpie
that had died. There was not any visible injury, I always wondered if
Tip gave it a heart attack or something.
The Magpies KNEW something was wrong with their friend, and did
everything they could to get him back. It was really, really sad in
its own anthropomorphic way.
Brenda,
South Weber