In 1969, after releasing two albums of blues music, Fleetwood Mac hit the top of the UK charts with Albatross, written by the group's founder, Peter Green. After a little searching on YouTube, I found a video showing actual albatrosses.
One of the most successful rock instrumentals during the early 1970's was Frankenstein by the Edgar Winter Group. Winter plays keyboards, sax and timbales on this track, and is joined by Ron Montrose (guitar), Dan Hartman (bass) and Chuck Ruff (drums).
Booker T and the M.G.s backed up many of the soul singers who recorded for Stax Records, but also put out some of their own music, such as Green Onions. The band consisted of Booker T. Jones (organ), Steve Cropper (guitar), Donald "Duck" Dunn (bass) and Al Jackson Jr. (drums). Cropper and Dunn later joined the Blues Brothers. Booker T. is also still active.
The Allman Brothers Band, after the untimely deaths of guitarist Duane Allman and bassist Barry Oakley, regrouped with bassist Lamar Williams and pianist Chuck Leavell. The new lineup released the album Brothers and Sisters in 1973, which included the instrumental Jessica, written by guitarist Dickey Betts.