PIFs - Puffins in flight!

I've been experimenting with various lenses for capturing puffins in flight on Skomer Island​ this season. This image was shot with the D810 and the new Nikkor 300mm F4 fresnel lens which is wonderfully short, light and easy to maneuver. It is a composite of five shots from a sequence of 6 of which one was out of focus and has been omitted. The resulting image is 834MB! The Nikon​ 70-200mm VR II gives a might higher hit rate of in focus images but the size of the puffin is correspondingly smaller. A 300mm on a full frame camera is the best option for capturing frame-filling shots. A 70-200mm on a cropped-sensor would be the best option.