Open Top "Baudry" style Bluebird Boxes on SR 25

One of my neighbors installed 4 open-top bluebird boxes on wood poles several years ago.

Prior to 1979, the North American Bluebird Society recommended these boxes because House Sparrows don't like to nest in boxes with open roofs.

But these boxes turned out to be deadly for bluebirds - adults, chicks and eggs.

NABS no longer recommends them.   People across North America reported nestlings were dying in the open-top box from hypothermia caused by wet nests and cold weather.  The Bluebird Restoration Association of Wisconsin (BRAW) which once recommended the open-top box, no longer does so.

I cleaned out the boxes then talked to my neighbor about what I found in them (dead adults, chicks and eggs).  He "modified" the roofs on the boxes - and is allowing me to monitor them.

Here's what they look like: