No facts? Yes, I shouldn’t have called them “gliders”, but the fact is that they don’t fly in the same manner as birds:
“Bats and birds, the only two vertebrate fliers on Earth, use their wings very differently”
They both fly by flapping their wings, but use the upstroke of the flap in different ways, with bats flicking their wings upward and backward unlike birds to gain lift.
“Bats seem to be mostly specialized for agile and maneuverable flight in complex environments,” Geoffrey Spedding, a University of Southern California professor of aerospace and mechanical engineering and one of the study’s authors, said by e-mail.
In broad generalities, bats are characterized by a darting, sharply turning and maneuvering flight. This can be seen as they wheel about catching insects, or flit from flower to flower,” Spedding added.
So the point about their wings serving different purposes and not being directly comparable in terms of efficiency stands.
Why can birds walk but bats can’t?