Hi Pat,
I have such a case coming up, where unfortunately the resident (a council tenant) didn't contact me until after the roof was complete, so it was too late to retain the nest sites within the eaves.
(In some cases you could cut an entrance hole in the horizontal soffit board in the original location so you could create a nest space that way,
but my case is an open eaves style roof so that's not possible.)
I'm putting boxes as close to the original locations as possible.
I'm mostly using Peak Boxes bottom-entrance boxes as from my limited experience these are the best ones for fast take-up, as Model 30s do get used but take an extra year or two.
I'll suggest they play calls from a speaker trapped by a window beneath the boxes, as I find they just go to the speaker if it's too close to the boxes. (A speaker inside the boxes hasn't ever worked for me.)
That's just my personal experience, others may well suggest differently and equally valid!
All the best,
Mike
Islington and Hackney Swifts Groups
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best advice to give to home owners?