Does not necessarily logically follow. If, in the experience of the namer(s), a bird that is big is encountered, then it is a reasonable thing to name it "Big Bird". Does not speak to the existence or non-existence of a "Biggger Bird", or a "Biggest bird", any more than it speaks to the existence or non-existence of a "Smaller Bird", or a "Smallest Bird".
(no subject)
(no subject)