20 November 1970 before the McCartneys returned to their Scottish farm for the Christmas holidays. Work continued at Studio B and A&R Recording Studios, New York, from the second week of January 1971 through to February. Playing guitar or piano and singing at the same time, Paul chose to overdub his bass later on. Although it was a collaborative project, Linda's vocal duties were mostly limited to singing harmonies and backing Paul, who sang almost all of the lead parts. Linda sang co-lead on "Long Haired Lady". The McCartneys' daughter Heather, who had been adopted by Paul the previous year, sang backing vocals on "Monkberry Moon Delight". "Ram On", from the album's first side, was reprised on the second side, before the album's final track, "The Back Seat of My Car". The New York Philharmonic was brought in by McCartney to play on "Uncle Albert/Admiral Halsey", "Long Haired Lady" and "The Back Seat of My Car", as well as the McCartneys' song "Another Day". "Uncle Albert/Admiral Halsey" is in a similar vein to the Abbey Road medley, as the song consisted of several unfinished songs combined into one. Music videos were made for "3 Legs" and "Heart of the Country", from footage that was filmed on 2 January 1971, and edited together five months later, by Ray Benson. The project was moved to Sound Recording in Los Angeles, where much of the backing vocals were recorded. Producer Jim Guercio cancelled his honeymoon to oversee the project, but his direction was not followed by McCartney, and progress stalled. McCartney was unable to choose which of the 20+ recorded songs would be cut from the album. Guercio left the project to honour a previous booking, and Norwegian engineer Eirik Wangberg replaced him, finishing the album over the course of six weeks. McCartney gave Wangberg free rein to mix the songs as he saw fit, and sequence them for the album in any way he chose. Among the creative decisions made by Wangberg was the stitching together of two songs to make "Uncle Albert/Admiral Halsey", and the introduction of thunder sound effects to that song; the thunder was taken from a monaural film clip, recorded by Wangberg onto two tracks with small differences to make artificial stereo. Paul and Linda were very happy upon hearing the final album mix. The recording project also yielded the independent single "Another Day" and its B-side, "Oh