An osprey on the hunt for breakfast perches above the James River south of Richmond, Va. The bobbing behavior shows that the osprey has spotted a potential meal in the river and is calculating the distance to the target by varying the angle of its head. Oct. 31, 2015. Nikon D7100. Tamron 200-600mm F/5.6-6.3. RAW. ISO 800. f/11. 1/4000th sec. 600mm (DX 90mm). -0.7EV. Click on image to enlarge.