Bluebird House Measuring Error (1 Viewer)

While attempting to make Bluebird houses for a local park, I misread the instructions. Instead of making the holes 1 3/8 x 2 1/4 inches, I read it as 1 3/4 x 2 1/4 inches. Will this impede nest success? Would it be worth it to replace the fronts?

With just about a 1/4 inch difference, it shouldn't affect its use. Heck I've had birds make my Bluebird box holes a wee bit larger by gnawing at the holes and it still didn't hamper the Bluebirds from nesting.

The concern is whether your houses becomes too accessible for competing nesters, especially House Sparrows.
Those will evict Bluebirds or kill them.

Note that http://www.sialis.org offers a plethora of relevant information for Bluebird trails and support.

i see you use a slot rather than a hole. just fix an offcut across it. there are many bluebird box designs with slots or holes of different sizes so i doubt it matters much unless you see predation and need to remedy it.

you can buy cheap metal plates on ebay in UK at various sizes. they are designed to stop predators from chewing away to get access, other birds, squirrels and more. so for a few cents you should find equivalent there.