@Thao_Nguyen, wow! these are undoubtedly some of the best American Kestrel pics I have ever seen.
I have lately been trying to find out more about these birds as they frequently visit the backyard of my aunt's house in Canada. I have found that building them a birdhouse can make them stay and reproduce, and so I have built one reasonably large one and put it up on a tree. But, the birds do not seem interested to go near it. Is there anything specific I was supposed to do? I know it may not be the right place to ask this, but I have tried other forums with no satisfactory results. Any help would be appreciated.