American Kestrel nest box

Step 22 Final tips and advice on kestrel-ing

Mount the box as high as your ladder will reach, 10 to 20' is ideal. Boxes should go in open areas, with the box opening not obscured by branches or other cover. Kestrels like to have an open approach vector to reach their boxes, as well as space to maneuver to prevent being captured by opportunistic bird hawks. Poles make ideal mounting substrates, but only use utility poles if you have permission from the company. Trees can be used, but be sure to use only nails or cables to attach boxes to trees. If using nails, put only one above the box and one below - if you use pairs, tree growth could easily split the box. You will have to check the box attachment annually and possibly reset it in order to accommodate tree growth. Sides of buildings, such as barns and sheds, or even on house soffits, can also be good options. In that case, painting the nest box to blend in with the house is acceptable, and the kestrels will still be able to recognize the cavity.

Our experience in Florida has shown that nest boxes do need regular maintenance to keep the boxes clean and safe, and to discourage interlopers (such as starlings, an exotic bird species, and squirrels, who have the ability to build their own nests) from taking over the boxes. If you cannot care for the nest boxes, they will quickly become useless for your target species. Note that native birds, such as screech owls, flycatchers, and bluebirds, cannot legally be harassed. In many states, squirrels are also considered a regulated game species. So check with your local regulations before evicting any non-kestrel residents other than the exotic starling or house sparrow.

You can find more information about caring for a kestrel nest box project at these websites:
Article by Cornell Lab of Ornithology
Kestrels Across America