Hi, we had success last with Blue Tits but the plate was 26mm so I can't say for sure but I would not think 1mm would make that much difference, no photos as I am replying on my phone.
Regards Shane
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Hi Robbie, I have 13 nest boxes up around the garden and the Blue Tits have used both 28mm and even an oval shaped entrance hole on a larger 32mm woodstone nest box with successful broods. When I read the current CJ Wildlife spring brochure 2018 (page 38) "Which bird, which nest box" page they suggest 28mm for Blue Tit and 32mm for Great Tit. I just measured a spare metal hole plate I bought a couple of years back for wooden nest boxes which have been used by Blue Tits in the past and they are 28mm. My verdict is to go with 28mm !!
Added note: if you have woodpeckers in your area then it is advisable on wooden nest boxes to fit a metal hole plate to the front and staple quarter inch wire mesh down the sides and underneath the box to prevent the woodpeckers destroying the box and predating any chicks.
Here's a pic with 28mm nest hole ...... and it shows how we protected the box successfully from predation
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Regards, Hazel
As on another thread, 25mm is fine. Many boxes are sold at 26mm and they are also fine. The 28mm option is also fine, but you are adding extra competition into the mix. As with the comments on the other thread, a new box will take time to attract occupants. If blue tits aren't using a 25mm entrance holed box, it won't be because of the entrance size. More likely better options elsewhere, or at least, better located options.
Just to add to Rob's reply, best position for situating a nest box is between North and East preferably; southerly position would get too hot in summer months - even our British summers !
Hi Robbie,
25mm is absolutely fine for blue tits. They can fit in and out with absolutely no problem.
Chris