Bert's best season from an offensive standpoint came in 1974-75 for the NY Islanders when he picked up 30 pts. He never scored more than 4 goals in one season.

"It was a one-man organization on the coast. With the Seals we had an owner (Charles O. Finley) who was never around and people under him who didn't have a free will to call the shots. Finley never knew guys' names and really didn't seem to give a hoot."
He stayed with the Seals until March 4, 1973 when he was picked up by the NY Rangers. His stint with the Rangers was short-lived. Bert played the last 8 regular season games there and 6 playoff games before the new arch rivals from Long Island, the NY Islanders picked him up in the intra league draft in the summer of 1973.
The Islanders passed on shifty center Bobby Rousseau who had won four Cups with the Canadiens and picked Bert instead. Ironically enough Bill Torrey, the GM of the Islanders had worked for two years in the Seals organization. His approach was however completely different than Mr. Finley's.
His coach on the Islanders, Al Arbour described Bert like this:

Bert was a member of the Islanders team until the 1978-79 season. He finished his career by playing 6 games for the Islanders farm team, Indianapolis Checkers in the CHL 1979-80. That same season NY Islanders won their first Stanley Cup. It was a shame that Bert missed that opportunity to hold the Cup above his head. He really deserved to win it.
Bert finished his NHL career with 868 regular season games, scoring just 17 goals but adding 181 assists for 198 points. And in 72 playoff games he picked up another 26 points.