Bird boxes

[NOTTM NUMPTY]

I am planning on making some bird boxes ready for next year, but I am not sure what size the holes should be, I know there are different size holes for certain birds, can anyone help. Thanks

[webbo3]

try here, it gives various sizes from sparrows boxes,blue tit boxes and even tawny owl boxes.
sizes of boxes ,holes and siting places ect

[webbo3]

sorry ,got distracted heres the link

http://www.lincstrust.org.uk/factsheets/nestbo x.php

[Thunderbird+]

A good rule of thumb if you want to encourage smaller birds ie tits is 29mm (11/8in) this will prevent larger birds like starlings etc using them. To stop the holes being enlarged a metal plate can be purchased from the RSPB.