Sorry, none of those guesses is correct, although I'm flattered
that you would think that I have an example of some of your more uncommon suggestions
being that I'm confined to the GTA.
Otto is not a flycatcher but it is associated with one of your other offerings, (hint).
Also, Boxer is positioned in a typical setting for this bird and there is
evidence of it in the photo snippet, as such lending its subject matter
to the bird's moniker (hint).
You're in the right ballpark with Rudolf.
Your guess for Blitzen is way off.
Vixen is a completely different bird family from guess of a sparrow.