Via basically everyone, this video is unbelievable. A golden eagle tries – and fails, thank god – to fly away with somebody's baby:
"This video is unbelievable" was clearly my subconscious being more right than I thought, because I actually don't believe this video is true.
A few people have watched it closer than I have, and frame-by-frame there are some things visible which are either very strange artefacts, or signs of a good CGI job.
Then there is the slightly odd motion of the child after the eagle lets go of it. Not only does it carry on going up - which would just be momentum - but its ascent actually speeds up a bit before falling .
Then there's the smell-test of the circumstances. The YouTube uploader joined yesterday, has never posted any other videos, and hasn't linked their account to anything else. If you're making a YouTube account these days, you have to make a special effort not to link that account to something like a G+ profile, and the uploader seems to have gone to that effort.
And finally, the Isle of Mull Eagle Watch team  think that that's not a golden eagle at all , but a juvenile eastern imperial eagle, which is not native to North America and unlikely to be hanging around Montreal parks.
None of this is conclusive evidence; but it's enough for me. I've changed the headline of this piece to reflect that. In the meantime I'm trying to find a way to contact MrNuclearCat, to get their side of the story.
It's confirmed: the video was a hoax by a Montreal animation school, Centre NAD :
The “Golden Eagle Snatches Kid” video, uploaded to YouTube on the evening of December 18, was made by Normand Archambault, Loïc Mireault and Félix Marquis-Poulin, students at Centre NAD, in the production simulation workshop class of the Bachelors degree in 3D Animation and Digital Design.