The RSPB have put out a reminder that now is a good moment to clean out nest boxes and put up new ones, since birds begin searching for likely sites well in advance of spring. And a sure sign that more nest boxes are needed in the area is when different species are found sharing the same space. This occurs particularly with barn owl boxes, since holes in trees or old buildings suitable for larger birds are becoming harder to find. The photograph shows barn owl and kestrel chicks being raised together. Great and blue tits are also known to share. RSPB