Green’s Dictionary of Slang

a group or team of enthusiastic (young) workers.

1951		R. Starnes Grant’s Tomb 101: ‘It is not legal to use it without the permission of the accused and that we were not able to get.’ ‘So you used it anyway?’ He looked at me wearily. ‘This is not the Beaver Patrol’.
1974		Bernstein & Woodward All the President’s Men 170: Both had been members of the ‘Beaver Patrol,’ composed of bright, fiercely loyal young men brought to the White House from the advertising and marketing worlds.
1974		J. Lahr Hot to Trot 223: ‘I’ve got enough to keep me busy.’ ‘So do I,’ Angie says, mugging like Groucho [...] ‘Back to Beaver Patrol.’.