Tyrannus tyrannus
Beckwith Township, Ontario, Canada.
These birds are well named in latin. Any invasion of their space; even by species MANY times their size, will invite their feathery warning flag; and immediate retaliation.
The scarlet crown patch is normally concealed by other dark crown feathers.
In this instance; and although the bird does look a little "pissed off"; I think it is the rain; and not my presence that caused the red "war paint" to appear. Streaks of rain may be seen in the background.
I know that if I had any such mechanism, I'd be flashing it in response to this miserable weather of late!!