First appearance = Whiz Comics #2 (February 1940) from Fawcett Comics.
(Remember, there was no "Issue #1" generally published for that title.)
In 1974, DC reprinted a story of Ibis' in an issue of Detective Comics,
and they also reprinted Whiz Comics #2 as a Famous First Edition (#F-4, at the expensive price of $1.00 U.S. back then!)
But Ibis' first appearance in a new story from DC Comics = Justice League of America #135 (October 1976):