This ruby-crowned kinglet literally jumped on the Tennessee warbler in the pond.
It may have been territorial or perhaps a misguided attempt to breed.
Either way the Tennessee wasn't amused.
I've not seen behaviour like this before.
The more you watch the more you see.
Tennessee warbler -Oreothlypis peregrina
Ruby-crowned kinglet -Regulus calendula
There is a yellow rumped warbler in the foreground.