Post by matt on Jun 8, 2020 12:24:15 GMT
Agree it seems small Karen, but I suspect it is fine. I've been making these concrete nest boxes with 11-12 cm circular base, and it is surprising how small they look inside (circle looks quite a bit smaller that 12x12 square, at least to me!). We know these small circular ones work, at least, because they are the measurements used by Schwegler for some of their blue tit boxes and by all accounts there work very well. Bear in mind that the nest itself is usually a good couple of inches in height, so the measurement for the chicks should be taken, say, 2.5 inches up from the bottom. How wide is it there? Having a smaller base low down might make it slightly easier on mum anyway, as it is less space to fill with nesting material. I would assume anyway that the makers/sellers of this box design have had success with it in the past?