At what age can buzzards breed?

[werdnal]

We usually have a resident pair of buzzards here every spring, who nest in a fir plantation about 200 yards from our house. Last year they left a fledged youngster behind who has stayed here over the winter and regularly visits our field and sits on a telegraph pole looking for food. He/She is a very light coloured bird, almost like a barn owl, so is most striking to look at.

We anticipated trouble when the pair returned, but it seems only one had come back. He/she is visiting the field and collecting sticks which they carry to the fir trees, so nest building is underway. This morning I noticed a very light coloured buzzard calling from the nest site, and receiving the sticks delivered by her "partner". Could this be the young bird who has been here over-winter? Would it be mature enough to bred in one year? If so, it seems to have replaced one of the pair (the parents) who has not come back this year?