Blue Tit bird house

The current entrance hole has a diameter of 28 mm, which is perfect to attract small tits (no pun intended :p ) : blue tit, black tit, European crested tit, willow tit, or marsh tit.

The balcony birdhouse offers much better protection of the nest:

Against predators: if a cat introduces a paw into the bird house, it will not be long enough to catch chicks at the bottom of the nest. Similarly, if a squirrel or a lerot tries to get in, the birds will be able to stand guard and defend the nest