Darkwing by Kenneth Oppel

Dusk's father is leader of the chiropters, bat-like creatures, on the island, but Dusk is not fully accepted. Chiropters glide through the air, but Dusk wants to flap his wings and fly. Dusk is able to use clicking sounds to help him see in the dark. The other chiropters are angry that he wants to be a bird, and the birds are angry when he actually learns to fly. A serious battle is brewing. Meanwhile, a side story tells the tale of Carnassial, a rebellious fetid. The fetids teamed up,with other beasts to destroy all of the eggs of a common enemy. However, eating the eggs gives Carnassial a taste for meat, so he starts secretly killing other beasts to feed his hunger. He's kicked out of his prowl for it, but his destiny will soon collide with Dusk and the chiropters.

I started reading this book thinking it was a sequel to Silverwings, but it's not. All of the characters and the setting are totally different. The names of the creatures in the book were based on real animals, but they're very early versions of the animals, like fifty million years ago. I had trouble visualizing some of the ground creatures. A theme in this book is definitely about conforming to the expectations of society while still having confidence in yourself. Dusk was afraid to tell his parents about his unique abilities, because he didn't want to get kicked out of the group. Carnassial was in the same situation. It was easy to see Darwin's theories, evolution, at work, as Dusk's abilities made it much easier to hunt and protect himself. To describe the plot simply, it's about predators, prey, and the food chain; animals trying to eat while not being eaten. Only the strong and cunning will survive.