the sky's the limit

for want of rotors, wings reciprocate
evolving out of parts already known.
The menu's fixed from which to innovate
'though some use exoskeleta, some bone.
The pterosaurs are gone, they've quit the skies.
The niche awaits a predator that soars.
For now, it's only gnats and dragonflies
exploiting lift in ridge, and wave, and cores.
The eagle spreads her pinions to the breeze
and gives herself to rising air's embrace.
Convection holds the liberating keys
for those not built to flap, who love the chase.
The latest innovators on the wing,
chiroptera squeeze in where birds are king.