I caught this little guy on a fence post along a road in the Pt. Reyes National Seashore (north of San Francisco). They are so skittish I rarely get close enough for a photo. This weekend however, I had a 500mm f4 from Lensrentals so with my 1.4 on it, I had enough firepower to stop a good ways off as not to scare him. I couldn't see the mouse with my naked eye, but when I looked through the viewfinder, I was pleasantly surprised.
Kestral with supper by lennycarl08, on Flickr