American Kestrel

I'd love to see the pic...animals do funny things...not always what's expected... ;-) You might want to contact a local raptor rehabilitator and see what they say about the nest boxes.

Nice capture! I think the kestrels might be eating things ON the agave flowers though...they are meat-eaters and will commonly take insects, rodents, small reptiles, etc...they do not eat flowers. Kestrels also nest in cavities...either made by other birds or in a man-made box. You can make or buy a kestrel nest box yourself...there should be dimensions on the internet...maybe you can get them to nest near you!!