Landlord's dilemma: Evict tiny tenants?

Photos by Jack McShane.

March is the time for putting up bluebird nest boxes, and cleaning out old ones. Watershed Post reader Jack McShane caught these little field mice red-handed -- er, red-pawed -- taking over a bluebird box on his property in Andes. He writes:

Spring cleaning of the bluebird boxes can result in a moral dilemma. Do I eject these little guys who have made cozy homes in my boxes so that they will be available for the bluebirds? Am I being racist, or I guess in this case speciest -- something that might be construed as immoral, bad ethics or just politically incorrect? Now the reality of all this is that these are my boxes constructed and erected by me for the bluebirds and these little (cute and terrified) creatures are after all squatters. Is it not my legal right to be a discerning landlord choosing whom, or what I will make my privately owned housing available to?

A tip on bluebird boxes: It won't keep field mice out of them, but if you put up nest boxes, consider putting them up in pairs a few feet apart. Swallows will often compete with bluebirds for nest space and keep bluebirds from taking up residence in a solitary box, but if the boxes are put up in pairs, the two species can be more or less happy neighbors, with bluebirds in one box and swallows in the other.

Here's more information on bluebird nest box spacing from the Tree Swallow Project. And here, an in-depth look at the science on the topic, from the Audubon Society of Omaha.