Beware of dog

Earlier from the second-story deck
I caught a glimpse of the gate
slamming shut as Ella chased
someone out of the yard.
Her wild barking was
what had summoned me.
The thunk of something landing
solidly on the wooden deck below
brought me down the stairs
to find a package for my wife,
too big to fit through the mail slot.
The gate latch was still vibrating
at a high B or C.