Here in Tokyo there vast numbers of very large and very loud crows.
Some ornithological estimates from 2008 say there are approximately 150,000 crows in Tokyo. I would assume there are a lot more now.
https://www.nytimes.com/2008/05/07/w...a/07crows.html
Crows are very attracted to mayonnaise (no idea why) and it is used to bait traps.
I have found they really dislike laser pointers being directed at them and they do not tend to return once the light has been directed at them.
Not sure if it would work with Canadian crows or magpies.