I was just getting some air outside of my office, holding my camera and looking for something interesting to capture, when I spied a Cactus Wren in a foot-pursuit of an insect. Dodging beneath various cactus instead of taking to wing, this bird caught my attention, and I brought up my camera and long lens to catch the act. These birds are amazingly fast and agile afoot, and this one's chase lasted but a few seconds.
Equipment: Nikon D-810, Tamron 150-600mm f/5-6.3g at 500mm, f/6.3, 1/2000 second ISO 1000.