Both appeared in Infinity Inc

Both are Golden Age offspring (SS is son of Hawkman I and Hawkgirl I, HM II is son of Hourman I)

Both gained powers from science ( SS was from his Nth metal suit, while HM II got his from Miraclo pills)

Both dated their teammates (SS dated Fury II, HM II dated Dr. Midnight II)

Both fought the Ultra-Humanite (SS in Generations Saga, HM II in Stealing Thunder)

A couple called "The Great Tits"
"The Blue Tit"
"The Blue-footed Booby"

there are loads like that...

How about "The Ornithologist". .. He collects people with bird connections... names linked to latin names of birds, etc.
Kills his victims, stuffs them and puts them on display...

In a costume themed to their name!

Gets stopped by Black Canary and Robin when he goes after the Penguin...

Episode called "Bird-Watching"...

I got two

The Cuckoo. He would kill robin and just show up in the bat cave like he was supposed to be here in a manner similar to the Cuckoo's laying eggs in the nests of other birds

Or

The Road Runner who would constantly avoid batman when the gadgets from his utility belt consistently fail.

Best thing about DC? NO EFFIN’ SKRULLS!

How would you know?

Best thing about DC? New Joe Kubert. The possibility of new Ambush Bug. `

Lived a peaceful existence until his or her environment was threatened by rampant development. Operates mostly at night and is very hard to see. Alter ego is very shy. Goes after envioronmental despoilers and big developers.

And because of diplomatic immunity, very difficult to convict. (closest to endangered species status I can come up with)

Fabian Nicieza ... I just can't get into him. Ever since the time he took over X-Men and did an incredibly blatant rip on Claremont's writing style I can't read anything he does.

BLACK VULTURE, Carrion Defiler!

I originally thought about creepy gimicks, because good Bat-villains need to be creepy AND to have solid gimmicks. And what's creepier than a villain specialized in stealing corpses for vile ends? That led me to the sort of birds that favour feasting on dead carcasses, and the rest came naturally. In a nutshell, the Black Vulture is a voodoo master who brings back the dead as zombies. Black Vulture has an arsenal of paralyzing herbs and poisoned darts that he uses to foil the Caped Crusader, and a giant vulture called Thanatos which whom Black Vulture has a supernatural link (Black Vulture can command his bird telepathically). Black Vulture wears a black cloak over a dark-grey suit, and his trademark is ceremonial face-paint that resembles a stylized skull. Batman will later discover that Black Vulture's ressurection formula is connected to R'as Al Ghul's Lazarus Pits, and that R'as' followers want the Black Vulture's head on a platter for having "perverted" the Lazarus Pits' mystical properties.

There are all sorts of stories that could be told with Black Vulture. For example, BV ressurects dead cops and politicians as zombies who give him privileged information that he then uses to blackmail still-living people. BV ressurects fallen superheroes and uses them as undead bodyguards, creeping the hell out of everyone. BV ressurects everyone on the morgue, building a zombie army that he then uses to wage a territorial gang-war against Gotham's living criminals, who are forced to ask for Batman's help against this ghoulish competition. This guy would be SO creepy that even the Joker would feel unconfortable in his presence.

This awkward, long-legged fop uses his awesome sonic powers and knowledge of Crane-style kung-fu to lethally take down big business in order to create a safe environment for his beloved, endangered brethren.

Though he'd probably work better as a Venture Bros. villain...