I recently posted to tweeters in response to a poster (Linda) who asked how to get Barn Swallows to nest elsewhere.

I suggested that, besides installing alternate nest box, she remove the old nests after the swallows were gone. Ed Newbold privately reminded me that Barn Swallows evidently choose their nest sites partly to take advantage of human activity to deter potential nest predators.

Hence, I'm modifying my previous advice. Install new nest boxes (actually, shelves), but try to put them where there will be human activity near or, better yet, inside a building or shelter with open access to birds. (Like, ahem, an open barn.) Leave the old nests up. If the birds choose the new location over the old, you will know you've chosen a good alternate site. Then, you can take the old nests down if they are in an inconvenient location.

Kelly Cassidy
Pullman