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Bird noises were dubbed in to this version to create a nature theme.This song is often cited as an example of tensions between Lennon and McCartney over treatment of each other's songs. When The Beatles went to record it in February of 1968, both Lennon and McCartney decided they wanted falsetto harmonies on the song. No matter what he did, John said he was sounding out of tune, so Paul went outside and grabbed two "Apple Scruffs" named Lizzie Bravo and Gaylene Pease to add the background harmonies.
John is quoted again about that, saying, "the original track was a real piece of s--t. I was singing out of tune, and instead of getting a decent choir, we got fans from outside. They came in and were singing all off-key. Nobody was interested in doing the tune originally." In another interview, he said, "The Beatles didn't make a good record of it. I think subconsciously sometimes we - I say 'we' although I think Paul did it more than the rest of us - Paul would, sort of subconsciously, try and destroy a great song... meaning we'd play experimental games with my great pieces, like 'Strawberry Fields,' which I always thought was badly recorded."
The two young women Paul grabbed off the street to sing backup appear on the World Wildlife recording of the song, but not on the version on Let It Be.