Nikon temporarily suspends orders for the Nikkor 500mm f/4E FL ED VR lens and other products, announces high demand for the new Nikkor Z DX 16-50mm f/3.5-6.3 lens - Nikon Rumors
My two cents on the D500 with Nikon 500MM F4 FL ED for Bird in flight: Nikon SLR Lens Talk Forum: Digital Photography Review
Nikon AF-S NIKKOR 500mm f/4E FL ED VR Review | Photography Blog