Does the Peregrine Fund have a recommended Kestrel nest box design? I'm sure I can find resources on line, but though I'd check first to see if you have recommendations. Also, how large a field is required to attract and sustain a pair of Kestrels?
"Our" Kestrels (in Benicia, CA, in the San Francisco Bay Area) hatched around May 10th, and the adults have been regularly bringing food, etc. The chicks are now quite vocal, but are not yet peaking out of the box.