Date: 6/24/19 5:41 pm From: David Jury via CTBirds <ctbirds...> Subject: [CT Birds] Wren boxes and House Sparrows
I can only speak from my own limited experience, but a box with a 1 and 1/8th inch entrance hole seems to be successful at accommodating house wrens or chickadees (though no other species) while excluding house sparrows. Knowing that house sparrows are common in our area and would be a potential problem, I purposely chose a box with a 1 and 1/8th inch hole after reading that 1 1/4 is the smallest size house sparrows can fit into. This is our third year of having that box in our back yard, and so far so good: the first year we had two successful broods of house wrens, last year we had a successful brood of chickadees, and this year we have house wrens again. Each year, house sparrows have spent much of the spring trying to claim the box, but have never been able to get inside. Eventually they realize that they can't fit, and give up and move on (though they can be rather slow and stubborn to admit it).