The Beavers are back!

As I was walking Rusty today we went along the "beaver stream".
About 5 years ago beaver dams began appearing along the stream. First there were a coupe of small dams, holding back small pools. Then the dams grew higher and the pools bigger. Eventually the pools were spreading over the fields that lined the stream and when the biggest dam was at it's highest, even the bridge across the stream was flooded.
At that point the farmer had had enough. One day I came down the stream and the dams had all been removed. The beaver lodges were high and dry and all the beavers seem to be gone.
Since then there has been no fresh sign of beavers, until today. Maybe they are on the way back.  I'm not sure - is this good news or not?