lots of 404

Hello, I migrate my web from blogger to wordpress, so I had to use the redirection tool to keep the google position sometimes, and I redirect with a 301 most of old directions to new ones. All ok about this.
The problem is that in the 404 redirection tool’s part, I see every day new 404 errors about pages that I think they are old, and I never used it with names like /?autor=1 to /?author=50, and a little more with names like/cwjjw54wc and characters that doest mean anything (my pages have always a name, /cars, /home, /footbalteams, you know what I mean) so I dont know what to do with this errors.

Any advice?