This one's from the New York Times Magazine and regards a short item last December that reported a grad student's claim that crows at the Binghamton Zoo had been taught to exchange coins for peanuts, and had begun scouring the ground for loose change. Excerpt of the editor's note in today's magazine:

The Times has since learned that Klein was never at the Binghamton Zoo, and there were no crows on display there in June 2008. He performed these experiments with captive crows in a Brooklyn apartment; he told the reporter about the Brooklyn crows but implied that his work with them was preliminary to the work at the zoo. Asked to explain these discrepancies, Klein now says he and the reporter had a misunderstanding about the zoo.

The reporter never called the zoo in Binghamton to confirm. And while the fact-checker did discuss the details with Klein, he did not call the zoo, as required under The Times’s fact-checking standards....

These details should have been discovered during the reporting and editing process. Had that happened, the article would not have been published.

Here's the original story.