The Paradox of an Avian Salivum

I can see a small bird in a tree
And the worm that it holds in its beak.
And I watch as it swallows it down
And regurgitates mush to its kin.
And I wonder why my (human) spit
Is not stored in the Registry for
Toxic Substances (also Disease).

Is it due to the fact that, in the absence of proper hydration, saliva takes on the same consistency as snot?