The environmental-themed program is produced and directed by Peanuts vets Lee Mendelsohn and Bill Melendez. Vincent Terrace describes it in his Television Specials: When a construction crew begins building on the sanctuary of a rare breed of California condors, the birds feel their lives are threatened. The story related their efforts to find No Man's Valley--a place where they can live in peace.
Oddly, Terrace lists the premiere date as September 12, 1983. Maybe it was rerun?
The cast includes Arnold Stang, Richard Deacon, Joe E. Ross, and Art Metrano (!) in addition to voice actors extraordinaire Henry Corden, Hal Smith, John Stephenson. I don't recall this show, but I plan to check out since Fuzzy Memories was nice enough to post it.