On 3 déc, 21:48, "'Mike'" wrote:
Many thanks Wally , Dave, Jim and John M.

All your points are noted and I am now wondering if I should get some nest
boxes with bigger holes and put them elsewhere in the garden for the
Sparrows and one more technical question. If the Blue tit is male and makes
a mess in the box over the Winter, should I when it's back is turned, clear
it out in the early Spring or 'let nature' take it's course? Gut feeling is
let nature do it, it certainly seems to be doing well at the moment ;-))

As a compromise you could throw in some of the powder used for
sanitizing bird-tables, though I would personally demount the box and
shake out any loose residues first.

As you are looking for all and any advice, try www.birdforum.net .
Select the "forums" tag and scroll down to " Garden Birds, Bird
Feeding and Nestboxes"