no TC. its ok.
my species is a fail too.
i need more info for them.
clevertheif managed. like wtf she drew a whole page thing like some kind of crazy scientist.
Glowans are awesome.
I really dont know how people do it.
really.

a caste system based on life span?

the preybirds then the songbirds and the birds of mixed genetics
...idek that probably wouldn't even work sorry

shh, take your time.
I've seen another bird based fanspecies, so maybe you should make yours water-based? idk
maybe their society is kinda split in two, where you've got water bird humanoids and flying bird humanoids. (just tossing ideas around here)
So really, any ideas could work. You could even take all of them, even contradictions, because it's an entire species, not just a character.
Think of what could differ between individuals, appearance-wise. Set a palette your species is allowed to use, maybe.
Then I guess you figure out their society and history and building style and other stuff you happen to think of.
Don't be afraid to use your weirdest ideas, they're aliens after all.
hope i helped?

whoops, that was one incredibly long comment.