The Owl here, but there was another hero (actually two of them in the same costume) based on the wise bird of legend.
The first Black Owl debuted in Prize Comics #1 as K the Unknown, but became Black Owl in #2. He didn't get a cover appearance until Prize Comics #7, which also featured the comic book intros of pulp hero Green Lama and literary character Monster of Frankenstein!
Now stop me if you've heard this one...
Bored millionaire playboy Doug Danville decides to battle cowardly, superstitious criminals as a fearsome creature of the night.
Utilizing his personal fortune, he creates a masked identity with various non-lethal armaments and takes on the criminal element for several years.
Sounds like a whole slew of heroes of the period, eh?
But there's a twist, folks!
When World War II breaks out, he enlists in the Army!
(Most heroes remained on the Home Front battling spies and saboteurs.)
Realizing it would be best for the city he protects if The Black Owl was still believed to be fighting crime, Doug passes on his costume and equipment to another man in Prize Comics #34...
Black Owl was Walt Walters, father of a pair of patriotic teen superheroes, Yank & Doodle whom Doug Danville had teamed up with on several occasions, most notably Prize Comics #24, when they, Green Lama and several other characters, took on the Monster of Frankenstein!
Once Dad became a superhero, the kids became his sidekicks, but remained Yank & Doodle, instead of renaming themselves something avian to match their father's motif!
(Luckily, their color schemes matched!)
When Walt is shot and wounded in Prize Comics #64, he retires from active crimefighting, serving as a non-costumed assistant to Yank & Doodle until their series is cancelled several months later.
Note: we never learn what became of Doug Danville after he entered the Army...
Alex Ross has now incorporated both Black Owls (and Yank & Doodle) into his Project SuperPowers Golden Age revival series, with one of the BOs somehow becoming a living black hole!
While we won't go that far, Atomic Kommie Comics™ has incorporated both Black Owls into our Lost Heroes of the Golden Age of Comics™ line, even giving them their own section featuring the first cover appearance as well as the best cover art for each Black Owl on t-shirts, mugs and other goodies!
So, whether it's The Owl or The Black Owl, we have something on WHOOOever (sorry, couldn't resist) holds your interest!
And buy Project SuperPowers, the best Golden Age revival series on the market!