Every year they're gone in the fall, taking apart the nest before they leave. Then they're back in March building a nest. So far each year there have been two chicks. I have no way of knowing if it's the same pair each year. The pole was put up for them to keep them off the power pole. They have a view of the Sanpoil river. More here http://www.flickr.com/photos/rockyraybell/ in the wildlife set.