There’s a hole in that

Laura A. Tyson et al. report an artificial nest cavity design that European Starlings (Sturnus vulgaris) don’t seem to like, or at least the starlings at their northern Ohio field test site. The team tested PVC tubes with a diameter of 10 cm, mounted horizontally and capped at each end, the opening restricted to 5 cm. Bluebirds, swallows, and wrens like the plastic boxes just fine, but no starlings used any of the 100 structures in two years of testing.