nest box hole size

[Steve JH]

Hello All
I am about to make some nest boxs for the garden,,I understand that the size of the entry hole is very important,
What is the size for Sparrows ? What is the size for Blue Tits and Great Tits,

Imperial size would be an advantage, as all my wood boring bits are in that size.

Regards Steve H

[nightshade]

All you need to know here National Nest Box Week - Make a nest box
25mm - 1"
28mm - 1 1/8"
32mm - 1 1/4"

Make some Bat Boxes as well
http://www.jwaller.co.uk/batgroup/bat_boxes.asp

[nightshade]

Think about adding a metal plate of the appropriate size if you have any
WoodPeckers in your area, I have just been sent photos of a nest box on
a wall outside a kitchen window. The woodpecker made the 1" hole into a
2" long hole and took the babies which had just hatched

[Elizabeth B]

We find these are too small - great tits can't/won't use a 28mm hole. We use this size for bluetits and 32mm for great tits.

All three boxes are now empty, but it's been a good year for us - though we've heard of many nest box failures. Box 1 had seven fledglings, Box 2 had ten and Box 3 had nine. Now we're seeing chicks perching near two of the hearts feeders, and parents running a shuttle service. (Our diary is being updated right now).

[diggleken]

I agree with Elizabeth, the oft quoted sizes are do-able, but a bit of a struggle, so slightly bigger works better.
Cheers
Ken

[nightshade]

I must admit I do notice Tits rounding off the access hole edges to increase the size. Nowadays I start the job off on new boxes with a half round file.
National Nest Box Week - Make a nest box, the link gives B.T.O sizes which I assumed were definitive

[Steve JH]

Thanks all, and Nightshade have all the information that I need

Regards Steve H