So it looks like my earlier theory — that the Perfesser has covered his floor in newspapers because he’s a bird, and shitting on newspapers on the floor of their home is what birds do — was something of a reach. It turns out that he’s just a hoarder whose home has reached such a state of chaos that he’s desperate to escape it. If you’re want an insight into his increasingly glum mental state, note that in the months since that cartoon linked above, he’s devolved from eating chips to picking from a bag of mysterious “SNAX,” presumably because he self-loathingly thinks that a guy with empty pizza boxes and tires strewn around his living room doesn’t deserve better than ambiguous snack-like foodstuffs to eat.
I’m not sure what this comic is supposed to be getting at in the context of Momma’s usual themes — maybe that the fly mistook Francis for a fellow loathsome pest? My preferred reading is that we’re being reminded that all creatures have a sense of self and will to survive, and that we perpetrate a thousand murderous tragedies a day without even realizing it.