In recent years there has been a marked change in distribution with a decline in the lower altitude woods with three woods losing their birds completely but there has been a corresponding increase in the higher woods with the medium altitude woods retaining their populations.
There is the possibility that the provision of more nest boxes in the upper woods that they have drawn birds away from the lower woods, but there is no support for this view from our ringing retraps. Another possibility we considered was an increase in competition from other hole nesting species such as tits but all our woods have plenty of unoccupied boxes. So the main conclusion was that the distribution changes related to ecological and possibly climatic change in the woods and we hope to set up a sampling program to compare occupied and un-occupied woods.
Our ringing over the years has shown that just 3.9% of the nestlings are recorded again. Of those that return to breed 34 % return to their natal wood-50% move to other woods within the Lune Valley and 16% move further afield Most of these are found in Northern England with smaller numbers from Wales and South West Scotland. Some though are more adventuress. Nestling ringed in our boxes have been found breeding in Germany and Denmark. It all helps to spread the gene pool.
By contrast adults mainly return in successive years to their native wood with just 15% moving woods within the Lune valley. A few do move further afield. One female ringed while nesting in Galloway moved to our area to breed next year, then north again to Cumbria the following year.