Wow. Max has one of these! You nature shooters can rent one now... far cheaper than buying one of these for the few times you need it. Sweet, Max!
BorrowLenses.com - Camera Rental and Canon/Nikon Lens Rental:
"The Nikon Telephoto AF-S Nikkor 600mm f/4G ED VR Lens is a premium ultrafast super telephoto lens, currently the longest in the Nikon autofocus lens system. It is a very robust and durable lens. Its lightweight construction incorporates a magnesium die-cast barrel, and professional-grade dust and moisture sealing allows it to be used in more rugged situations.
This lens features the improved Vibration Reduction (VR II) system that allows handheld telephoto shooting, even in less-than-ideally lit conditions. The VR system minimizes image blur caused by camera shake, and offers the equivalent of shooting at a shutter speed of about 4 stops faster. In addition, this lens also features the Tripod Detection mode, which reduces vibration that may occur due to shutter release, when mounted on a tripod."