Do wind turbines blades all rotate at the same speed?

 

It's been incredibly windy at Watchtree but the turbines never seem to spin faster. In other words, their angular velocity seems to be the same. Is this true? There is a wonderfully detailed discussion of the topic here. It seems that once the blades are turning at the most efficient speed, they adjust the angle of the blades as the wind blows harder to keep at that speed.