The US Postal Service unveiled a new stamp honoring great American writer Maya Angelou this morning. It features a grinning picture of the author and a lovely, inspirational line of poetry. There's just one problem: It's not a line of Angelou's poetry. The Washington Post reports that the chosen phrase, “A bird doesn’t sing because it has an answer, it sings because it has a song,” is actually a slightly edited line from poet Joan Walsh Anglund’s 1967 book A Cup of Sun. Anglund confirmed with The Post that the words are hers. The USPS defended the stamp in a statement to CNN, saying that the quote was widely (mis)attributed to Angelou — even President Obama quoted it as hers in a 2014 speech. The confusion likely stems from a connection with the title of Angelou's autobiography, I Know Why The Caged Bird Sings. While Angelou was the recipient of numerous awards during her lifetime, this was to be the first stamp to honor her. She died in 2014. The USPS hasn’t said whether or not it will reissue the stamp with a new quote, but for now the incorrect one is still for sale on the Postal Service website. In the meantime, if you'd like to check out some great quotes that Angelou actually wrote, we've compiled them here.