On April 7, First Lady Michelle Obama, as well as Oprah Winfrey, Angelou's grandson, and Nikki Giovanni, participated in the ceremony unveiling the U.S. Postal Service's Maya Angelou stamp. Angelou certainly deserves a commemorative stamp. In addition to her writing, she was a dancer, singer, and actress who participated in the Civil Rights Movement of the 1960s.
Angelou's stamp includes a quote she often recited: “A bird doesn’t sing because it has an answer, it sings because it has a song.” While she is closely associated with the quote, she didn't write it. It was actually composed by Joan Walsh Anglund and published in her 1967 book A Cup of Sun. The post office is not reissuing the stamp. USPS spokesperson Mark Saunders wrote to The Washington Post, "Had we known about this issue beforehand, we would have used one of [Angelou's] many other works. ... The sentence held great meaning for her and she is publicly identified with its popularity." To be fair, the USPS wasn't the first to misattribute the quote. President Obama did it himself in a 2013 speech.
This does remind me of another USPS snafu in 2011 when a Statute of Liberty stamp, which the post office thought had a photograph of the New York landmark, was actually revealed to be a picture of the Las Vegas replica.
New York Times Article - Maya Angelou Stamp
New York Times Article - Statue of Liberty Stamp