Okay, I’m still obsessing on my catbirds.
I see the parent catbird going from perch to perch with something in its beak, presumably a tasty morsel for the baby catbirds (kittenbirds?). It is also chirping away (why? signaling the babies? signaling other birds) – but its beak stays firmly closed around the morsel.
Does the chirping happen further back in its throat, or what?