Why on earth is Montreal covered in feathers?

Montrealers are normally nonplussed by white ground coverings. Snow happens; life goes on.
When a white substance covers the ground in the middle of summer, on the other hand, a few raised eyebrows are unavoidable.
That’s exactly what happened over the weekend when Montrealers went outside and found feathers everywhere. Or, as another Montrealer succinctly stated in a Facebook post: “All of place des arts is full of bird feathers wtf.”
The explanation for this phenomenon,