The Northern Neck Audubon society undertook a project to help increase American kestrel population by building kestrel nest boxes or houses. Leslie Fellows, a NNAS board member, has written an article on how and why the Northern Neck Audubon Society has done this.
American Kestrels are our smallest falcon and are declining in numbers due to habitat loss and the widespread use of insecticides which kill the insects and small animals that they need for survival. Kestrels are cavity nesters and a properly sized nest box will provide an ideal home to raise their young.
Dairy, cattle, and horse farms make excellent locations since their fields are not sprayed with insecticides because of the grazing by those animals. But any open fields that aren’t sprayed with insecticides are good candidates. Barns are excellent structures for mounting the boxes. The added advantags to having kestrels around is natural insect control. Eastern Screech Owls, another of our birds in decline, could use these nest boxes too.