That's a good point. With the use of Merlin and Raptor I guess SpaceX is looking to stick with actual birds of prey. While attempting to relate this to BFR, I looked up the largest known falcon in the world. It's called the Gyrfalcon (Jeerfalcon?). Unless your an Audubon member or ornithologist it might be too esoteric for the Falcon series. Although with Elon, guess we can never rule anything out!
Hello?
Yes, "gyrfalcon" is indeed pronounced "jeer..."
Howifinever...........that fantastic creature very often is referred to solely as a "gyr". Wherein we then can see some setup whereby SpaceX dubs one of its craft "Gyr" as a moderately subtle way of jeering at - who? ULA? NASA? Dunno.
PS: We're one of the lucky, lucky very few people on earth to have gyrs as backyard birds. True!