Penguin is the only Fleetwood Mac album to feature Dave Walker.
Walker joined Fleetwood Mac in September 1972 after Danny Kirwan’s departure. Formerly a vocalist with Savoy Brown and the Idle Race, he was brought in as the band sought an additional frontman. Guitarist Bob Weston joined at roughly the same time, creating a short-lived lineup that recorded Penguin.
Released in 1973, Penguin was recorded in Hampshire at the band’s communal house, using the Rolling Stones Mobile Studio rather than a conventional London studio. Walker’s presence is central to the album’s unusual place in Fleetwood Mac history, but he did not remain for long. During the recording of the follow-up, Mystery to Me, the band decided that his vocal style and attitude were not a suitable fit, and he left by June 1973.
That departure creates the common mix-up: Walker was associated with the period around Mystery to Me, but he did not appear on that album. Penguin is therefore the decisive answer, while Future Games and Bare Trees belong to earlier lineups that did not include him.