The bird sings "Poo-tee-weet", a nonsensical phrase that is meant to show the illogical and absurd nature of humans killing humans that make them appear as machines to the Tralfamadorians.
The Tralfamadorians also find Billy's concepts of free will and death to be absurd. The Tralfamadorians argue that there is no such thing as free will, it is only an illusion maintained by humans. There is no free will because time exists simultaneously to the Tralfamadorians and is not linear in nature. All moments of time have already happened so the Tralfamadorians adopt a fatalistic view of their universe. Where death is concerned, the Tralfamadorians have a catch-phrase that is uttered every time they see a dead body, "So it goes," (Vonnegut 1969, 27). The phrase is repeated throughout the book to illustrate the futility of life and death in a machine-like world where war and mass killing are routine. Each moment is meaningless in a machine-like world where humans not only treat death casually but, therefore, life as well. Billy explains for us the view of Tralfamadorians on the dead, "When a Tralfamadorian sees a corpse, all he thinks is that the dead person is in bad condition in the particular moment, but that the same person is just fine in plenty of other moments. Now, when I myself hear that somebody is dead, I simply shrug and say what the Tralfamadorians say about dead people, which is ŠSo it goes,'" (Vonnegut 1969, 27).
In conclusion, the fact that the Tralfamadorians view all creatures and plants as machines reinforces Vonnegut's themes of the absurdity of war, human actions, and human motives. In Vonnegut's religion, evil is balanced by those who refuse to let it direct them. War is clearly presents as an evil, with the Dresden slaughterhouse being an example of how such evil is manifested. That Billy is distanced from the Tralfamadorians and them from him, with respect to perspec